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Forum: Pentax SLR Lens Discussion 03-07-2016, 04:02 PM

Macro lens bake-off!
Posted By lmd91343

Replies: 43
Views: 5,836

Note 1:
If you want me to upload any full images or detailed sections of an image, ask. I've tried to post images, so my points could be followed and verified. With the reduction of image detail density required for web posting, some discussion points may not be easily seen. I used enlargements in PS and LR for analysis.

Note 2:
My near infinity test image test analysis and image mosaic construction is not complete due to my arm injury. I will complete that missing detailed "Results" section above and the conclusion paragraph below after I am healed. From initial analysis, it should not change my opinion stated below. If I find contradictions to that, I will post a "red letter" edit and an additional posting.

Note 3:
In normal use of my Takumar, I normally use about -1/2 to -1/3 of a stop of exposure. I did not do so in these tests.

Note 4:
I still have plans for teleconverter vs. extension tubes vs. “vanilla” comparisons. I will also run a set of tests on my Vivitar 90-180 flat field lens.

Conclusion:
My initial working hypothesis was that all 100mm -ish macro lenses have good IQ. Differences as to what constitutes a better lens must be made based on other attributes. I feel that I was mostly right.

Using any of these lenses on my K3 without comparing the IQ it to another lens leaves me happy with the results. I would not wish for a different lens. Therefore any ranking of these lenses must be based additionally on other non IQ parameters. However, I did compare the IQ on these lenses. ;)

The detailed relative resolution comparison of these lenses showed they were all about the same, very, very good. Extreme enlargement of the closest focus point images, there may be a very, very small difference that changed between the .5X and the 1X reproduction ratio images. One time the Takumar was the best by an exceedingly small margin, the other time it was the worst by that same very, very small margin. This was probably due to a failing in my manual focusing abilities. This could only been seen under extreme enlargement, to the point of pixelation. Looking at something one quarter of a millimeter wide and enlarging it to fill 23" monitor is beyond expected macro lenses use. Macro lenses are not designed for that degree of enlargement. A more reasonable approach would be to use bellows for that degree of enlargement. Winner: TIE

Vignetting testing also produced exceedingly close results. The Takumar and the D-FA were almost identical and almost perfect. The Phoenix was 1/16th of a stop darker in the corners than the Pentax built lenses when wide open. That does not merit any negative points. Winner: TIE

Color testing produced a result unexplainable by me. All three lenses produced almost identical measured color values on red and green objects and varied by up to six percent on the blue object. All three lenses behaved the same. Winner: TIE

Purple fringing testing produced almost equal and perfect results with attempts to provoke a defect. Winner: TIE

Distortion and decentering testing produced equal and perfect results amongst all three lenses. Winner: TIE

Test image with .5X magnification produced images almost equally sharp images with very slight differences probably due to my focusing. Winner: Tie

Test image .25X magnification also produced images almost equally sharp images with only very slight differences probably due to my focusing. I was most comfortable with my focusing in this test. With only a moderate amount of magnification small differences were found. In order of sharpness: Takumar, D-FA, Phoenix. Because the differences are small and I cannot rule out focusing mistakes, I declare a tie.

Near infinity test image test analysis is not complete. I cannot finish it until my arm heals. My initial impression was that all were very close is sharpness. Bokeh looked very similar too. I will return to this section when my arm is better.

The Takumar was the easiest to focus manually in sufficient light by virtue of its large focus ring. Winner: Takumar The D-FA by virtue of its wider aperture was easier to focus in less than perfect light. Winner: D-FA

The D-FA has both auto-focus and full time manual focus, the Phoenix auto-focus only, and the Takumar has no auto-focus. Winner: D-FA

With respect to lens automation, the Takumar has only auto-aperture, useless with modern K cameras, and both the Phoenix and the D-FA have fully automated aperture control. Winner: D-FA and Phoenix

The readability of the scales and easy manual focusing, the Takumar is the obvious choice if exacting measurement of reproduction ratios are needed. I have not needed that for a project for over thirty years. In the digital age, end result sizing can be controlled with photo manipulation programs negating the need for precise reproduction ratio measurement on the lens.

Overall these three lenses are all excellent as judged by their results. They are all well corrected full frame lenses used on an APSc camera. The Takumar was designed as a professional lens when the Spotmatic was the professional SLR of first choice (the only popular one having TTL metering). The D-FA is a lens of modern design planned as a high end optic. It is not surprising that these lenses are excellent performers. What is surprising is that the Phoenix can be compared to them.

All the Takumar IQ parameters were almost the same as the D-FA. I know of no advantage the Takumar holds with the exceptions of the scales readability, aperture ring, and the large focus ring. What the D-FA additionally has that the Takumar does not, is the aperture controlled by the camera, weather resistance, and auto-focus with full time manual override. The D-FA also extends to 1X magnification compared to the Takumar's .5X magnification. The Takumar will get relegated to the back of the shelf, only to be used on my bellows. What I will miss is that large focus ring. I usually do not use auto-focus for high magnification shots. The D-FA can also be used as a short auto-focus telephoto lens. This allows me to move my beautiful 105mm f 2.8 Super-Multi-Coated Takumar to retirement alongside my newly retired Takumar macro.

The Phoenix, though cheap and clunky in appearance, competes in IQ at a level on par or just below the two Pentax lenses. How did they do that? Only on the one test at .25X magnification of my wife's miniature collection did the Phoenix show an observable lesser IQ than the Pentax lenses. That deficit is minor. Where this lens fails is in comparison, is in usability. It is a bit harder to focus manually than the Pentax made lenses. It is also hard to read the scales on the lens, the D-FA and the Takumar are better. The aperture ring has only full f stop clicks. I'll be using the D-FA, not the Phoenix, because of the slight IQ difference that can be occasionally seen, weather resistance, and the full time manual focus override. This lens will go for sale or moved to the back of the bottom shelf.

The D-FA lens, IQ wise just about on par with the Takumar and occasionally slightly ahead of the Phoenix, suffers from no aperture ring, a small focus ring, front lens element not deeply (only 5mm) recessed, and a funky lens shade arrangement. With the D-FA, I'll just need to take an extra lens hood with me when I plan on using magnifications greater than .5X. However, it is my choice for the best of the three lenses. It has great IQ, weather resistance, better manual focus ability than the Phoenix, and faster aperture than the other two lenses. It can extend to a reproduction ratio of 1X, which I have never used. Given its speed and ease of use, it also will make a great general purpose short telephoto lens. Plus it is cool looking, very similar to my DA Limited lenses!

Forum: Pentax SLR Lens Discussion 03-04-2016, 02:38 PM

Macro lens bake-off!
Posted By lmd91343

Replies: 43
Views: 5,836

An interesting observation to note in “Test image .25X Magnification” and in the “1:! Resolution macro 100mm lens test” is that the exposure levels of the Takumar and the D-FA stay close amongst the varying apertures, i.e. the Takumar f 5.6 and f 11 are close to each other. The Phoenix on the other hand, increases its exposure as the aperture narrows. In close examination of all my "series" images, it is present. It is easiest to see in these two.

Does the iris not narrow as much is it should? Is it sluggish? Is it something in the K3 light meter firmware? Probably a quirk of the lens itself. I have never noticed it before. I'll try it on my other DSLRs in the near future.

Obviously this is minor. I've worked around it for a while without noticing it. This is the largest differentiating factor between the lenses. It would not prevent me from using this lens.

Forum: Pentax SLR Lens Discussion 03-02-2016, 03:57 PM

Macro lens bake-off!
Posted By lmd91343

Replies: 43
Views: 5,836

What does this information mean in terms of changing lens design?

Thanks!

Forum: Pentax SLR Lens Discussion 03-01-2016, 08:47 PM

Macro lens bake-off!
Posted By lmd91343

Replies: 43
Views: 5,836

I think this is what you want:
Tak: 2:1 = 1.48'
Phoenix: 2:1 = 1.41'
D-FA: 2:1 = 1.25'

Tak: 1:1 = 1.1' with the Phoenix dedicated adapter
Phoenix: 1:1 = 1.41' with dedicated adapter
D-FA: 1:1 = .95'

Forum: Pentax SLR Lens Discussion 03-01-2016, 04:27 PM

Macro lens bake-off!
Posted By lmd91343

Replies: 43
Views: 5,836

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Note:
Today's posting should have been the "Far focus and bokeh test" section. However, I hurt my right arm and shoulder a few days ago and have been unable to use a mouse or my right hand for typing or photoshop. Therefore I cannot construct the photo mosaic for this section or do the detailed inspection of the images.

The little I did glean from the far focus tests is that the sharpness of the lenses were exceeding close, hard to tell apart. The D-FA was the easiest to focus due to the relatively fast aperture compared to the Takumar. The Phoenix was in the middle.

The good news is that all the other sections were completed two weeks ago before I hurt myself, except for the far focus portion and a part of the conclusion. I'll post the remaining sections and finish the far focus later (a week?) then post it.

Eventually I will get to the teleconveter testing and the Vivitar 90-180mm test.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Today's results
The color test was done by checking the 3X(0-255) RGB values on .5 magnification test images. The images were of my dedicated slide scanner calibration slide placed upon a daylight color slide table. Lightroom and Photoshop were set to sRGB color space. RGB values were found from the (gross)blue K22, (gross)red L17, and (gross)green F4 squares from images of equal luminosity across lenses.

The (gross)red and (gross)green squares matched each other across all three lenses with respect to the RGB values, with a difference of 1% or less. The (gross)blue square had blue portion values that matched across lenses, however the red portion and green portion values varied by 6% and 4% within that (gross)blue square between lenses. In other words, the (gross)red and (gross)green sections matched exactly and the the (gross)blue section varied slightly. Overall the Takumar and the Phoenix were closer to each other than the D-FA lens with respect to the six larger variations from (gross)blue K22. Statistically, 21 of the 27 values matched within 0-2%, three values within 4%, and three values within 6%.

I do not know the significance of these variations. I do not know which lens is closest to “correct”. I can only report that. the data is presented in RGB triplets for each lens in each color square. This is not a pattern I expected..

To my naked eye, they all look the same. The lenses are interchangeable.

. . . . . . . . . . . . . Takumar . . - . . Phoenix . . . - . . . D-FA
Green F4 . . 035, 072, 037 . - . . 035, 075, 038 . - . . 035, 078, 038
Red L17 . . 079, 021, 022 . . - .. 080, 020, 022 . . - . . 079, 016, 022
Blue K22 . . 017, 018, 030 . . - . . 010, 013, 028 . . - . . 002, 007, 030

Forum: Pentax SLR Lens Discussion 02-28-2016, 11:11 PM

Macro lens bake-off!
Posted By lmd91343

Replies: 43
Views: 5,836

These test images were taken on my tripod illuminated by daylight lights. They were manually focused using focus peaking by moving the tripod on the floor. The target is my part of wife's miniatures collection. I focused on dust particles on the blue knob in the center. The lens was set at the reproduction ratio and not changed. The entire image is presented along with a 15% section from the center on the f 4 exposures.

I can see no difference in sharpness between the Takumar and the D-FA. Here the Phoenix is just a touch less sharp. On the f 4 images, pay attention to the dots around the central portion of the flower on the small central two handled urn. (f4 is wide open on the Takumar.) It is noticeable that those dots on the Phoenix are not as distinct as on the Takumar and D-FA. It is not as noticable on the uploaded jpegs as on my PS at home, but the effect can still be seen. The exposure on the Tak is is slightly greater than the D-FA. The exposure on the Phoenix gets greater as the aperture gets smaller as seen in the previous section. I have noticed no difference in bokeh between the lenses. I am not a good judge of bokeh. Of all my tests this is the one am most comfortable with the focusing.

Forum: Pentax SLR Lens Discussion 02-28-2016, 03:30 PM

Macro lens bake-off!
Posted By lmd91343

Replies: 43
Views: 5,836

Thank you.

Maybe, maybe not. Mea culpa.

I shot the Phoenix first. Then I knocked over the lights with my elbows and hit the watch when I removed the camera to change lenses. I repositioned the lights and watch where I thought they were. Then, I reshot the sequence at the same settings. Then I knocked over everything again when I removed the camera to change to the Takumar. Of course I put the lights and watch back to where I thought they should be and reshot at the same settings. I was not looking toward comparing contrast here, only sharpness, so repositioning the lights and watch did not concern me. This was the only test where I did knock over the lights and subject.

On the previous test, the white to black scale, in 24 steps, shown on all exposures, indicates good contrast for all to me.

They sequence that I will post tonight will be much more instructive as to contrast and sharpness than anything I have posted up to now. It is a still life of miniatures that my wife collects captured at .25X magnification.

Forum: Pentax SLR Lens Discussion 02-27-2016, 06:22 PM

Macro lens bake-off!
Posted By lmd91343

Replies: 43
Views: 5,836

These test images were taken on my copy stand illuminated by daylight lights. They were manually focused using focus peaking by moving the head on the copy stand. The lens was set at the reproduction ratio and not changed. The central 9% of the frame is presented. The second hand on the watch was moving during the exposures. I found these images difficult to focus.

Upon examination it appears that the D-FA is slightly sharper than the Phoenix, which in turn is slightly sharper than the Takumar. It is only apparent with great magnification. This may be an artifact of my manual focusing. When the entire image is displayed at 8”x10” size I cannot see any difference. In this instance I found the D-FA the easiest to focus, followed by the Phoenix, with the Takumar in last. That is the order of the widest aperture of the lenses.

If I required magnification so that a watch without straps filled both the digital image and an 8”x10” print, I would use any of these lenses interchangeably. If I required greater magnification, I would probably use bellows to grab enough image/data density. That would of course negate the value of the slight sharpness increase that the D-FA MIGHT have.

Forum: Pentax SLR Lens Discussion 02-26-2016, 05:46 PM

Macro lens bake-off!
Posted By lmd91343

Replies: 43
Views: 5,836

This resolution test was conducted using a dedicated negative scanner’s calibration slide. The slide, already encased in a special holder, was placed in the carrier and set upon the light table, which in turn was placed upon the copy stand baseboard.

The calibration slide contains no resolution measurement information. It was used to find any differences between the lenses. This calibration slide has very sharp, fine lines printed upon it. I used the black on white and black on gray sections for my observations.

I could find very little difference between the lenses. However as with the 1X reproduction ratio test, when enlarged to pixilation, I could possibly discern a very, very slight increased sharpness with the D-FA lens over the Phoenix and the Phoenix over the Takumar by counting fuzzy pixels around image elements. That is opposite of the 1X test! I attribute that to focusing error on my part. I had to count pixels on extremely large enlargements, beyond anything reasonable for a macro lens alone.

I would use any of these lenses to take these kind of images. Essentially, the lenses are equal.

The images presented below represent about 56% of the central portion of the image.

I forgot to put f stop notations on the composite. The first row is 2.8, the second 3.5, third 4.0, fourth 5.6, fifth 11, sixth 16. -Sorry

Forum: Pentax SLR Lens Discussion 02-25-2016, 06:27 PM

Macro lens bake-off!
Posted By lmd91343

Replies: 43
Views: 5,836

This resolution test was conducted using a dedicated negative scanner’s calibration slide. The slide, already encased in a special holder, was placed in the carrier and set upon the light table, which in turn was placed upon the copy stand baseboard.

The D-FA lens natively will enlarge images to 1X magnification, and the Takumar and Phoenix lenses only to .5X magnification. The Phoenix comes with a dedicated supplemental lens that aattaches to the filter threads on the front of the barrel. That supplemental lens was used for this test on both the Takumar and Phoenix.

The calibration slide contains no resolution measurement information. It was used to find any differences between the lenses. This calibration slide has very sharp, fine lines printed upon it. I used the black on white and black on gray sections for my observations.

When the images were enlarged in Photoshop to fit my 23”monitors, I could not see any difference between any of the three lenses. Surprisingly, when the smallest portion, close to 5% of the image was enlarge to actual pixel size pixilation, the Takumar, was the very slightly sharper than the Phoenix, which in turn was very slightly sharper than the D-FA. It took 20 minutes of very careful checking. I saw perhaps a one or two pixel more of fuzziness This finding might be the result of focusing inaccuracies on my part.

I would use any of these lenses for this kind of work.

Presented below is about 10% by area of the image taken from the lower right corner from every lens at every aperture.

]

---------- Post added 02-25-16 at 05:28 PM ----------

I appreciate the note.

Forum: Pentax SLR Lens Discussion 02-25-2016, 03:56 PM

Macro lens bake-off!
Posted By lmd91343

Replies: 43
Views: 5,836

We have had a discussion about the appropriateness of lens hoods for these 100mm macro lenses. I said that I would run a quick experiment to see if a more appropriate lens hood could be used for shade and protection.

I made the observation that the D-FA hood does not move with the inner lens barrel. This leaves only 5mm of lens hood to shape and protect the front element of the lens at closest focus. The front element of that lens is recessed only a paltry 15mm. This gives only 20mm of shade and protection to the lens. This compares poorly with its Takumar ancestor with a front element recess of 20mm and a factory lens hood of 49mm for a total of 69mm of shade and protection at any focus position.

Two sets of tests were made. The first a high light angle of 60*, with a 75mm hood and also a 49mm hood. The second set of tests is based on a moderate light angle of 45*.

The first image is that of the lens mounted on a K5 with the closest lens focus set and the camera placed at that distance. This was confirmed by a live view check. The red object placed centered beneath the lens is the same size as the camera's APS sensor.

The second photo shows the lens, red target object, 49mm lens hood and a 30-60-90 drafting triangle with a blue color on the hypotenuse side. That blue color represents the light ray closest to the edge of the hood. With the 49mm hood, that light ray falls across and beyond the target area as indicated by the blue line covering the entirety of where red object touches the white paper underneath. This shows that the 49mm hood is the right size or too short.

The third photo shows the lens, red target object, 75mm lens hood and a 30-60-90 drafting triangle with a blue color on the hypotenuse side. That blue color represents the light ray closest to the edge of the hood. With the 75mm hood, that light ray falls just short of illuminating the target area as indicated by a portion of the red object touching the white paper underneath, not hidden by the blue triangle edge. Notice that you can seen where 2-3mm of the bottom of the red object and white paper interface. About 17mm of that object/white paper interface is covered. This shows that the 75mm hood is just barely too long.

I have not posted the photos for the 45* moderate angle light ray. If the 60* light ray clears or barely misses clearing the shallower 45* ray will easily clear.

The 49mm hood is the factory dedicated one for the Takumar 100mm macro. The 75mm lens shade is the one dedicated to the Takumar 200mm f 5.6 lens.

These tests are for APSc only.

Forum: Pentax SLR Lens Discussion 02-24-2016, 10:35 PM

Macro lens bake-off!
Posted By lmd91343

Replies: 43
Views: 5,836

The tests were conducted using my K3 on a copy stand with a sheet of graph paper taped to the baseboard, illuminated by daylight bulbs. The graph paper had a grid of lines at a 1.08mm spacing. The photos were taken at .5X magnification. All focusing was done manually. All apertures on all lenses were used.

When displayed at several different magnifications on my 23" monitor, all the lines on the grid where perfectly straight and normal to each other. All the images from all the lenses had a slight contrast loss in the lower right corner, created perhaps by the manner in which the lamps were set. I cannot tell one image from another as they vary by both taking lens and aperture. They are all equally sharp and undistorted. These lenses produce images equally sharp across the image.

No decentering was found any any image. All lenses amongst each other and all apertures. All apertures appear to be the same. Each of the four corners were compared to the other three. Only the decentering test image is displayed from f 4.0.

I would not worry about distortion, field flatness or decentering with any of these lenses.

Forum: Pentax SLR Lens Discussion 02-24-2016, 10:53 AM

Macro lens bake-off!
Posted By lmd91343

Replies: 43
Views: 5,836

Purple fringing was tested by acquiring the same image from each lens at every full stop. The subject matter was selected in order to provoke purple fringing. The images are of bare tree branches against a bright blue sky. The bark is very light in color, the shadow side dark. These branches are more than 100 feet and less than 200 feet away. The images were captured with a light breeze during the break of a wind storm. The images presented here are extremely magnified from the central 0.4%, by area, of the capture. It is highlighted in yellow in the center of the index image.

All three lenses presented a very small amount of purple fringing, one pixel wide, as shown on my monitor in PS6 from the raw images when enlarged to the point of pixelation on actual pixel size setting. The samples from all three lenses, along with an index image showing the area of enlargement, are shown below.

With respect to purple fringing all three lenses are near perfect.

Forum: Pentax SLR Lens Discussion 02-23-2016, 03:08 PM

Macro lens bake-off!
Posted By lmd91343

Replies: 43
Views: 5,836

Vignetting was checked by taking a picture of a uniformly painted and uniformly illuminated interior wall. The camera was placed on a tripod five feet from the wall and manually focused. Images were captured at all apertures on all lenses. Images were also captured with the original factory lens hood at the widest aperture only. As there is no factory hood for the Cosina/Phoenix, I used the 105mm Takumar lens hood, which is 38mm deep. For comparison, the original factory hoods for the Takumar and the D-FA SMC WR's are 49mm and 55mm deep.

I desaturated (removed the color) each image. Using the PS eye dropper (3X3) tool I measured the color value at the center of the image, half way to the corner, and in the corner of the left lower side, averaging several samples at each spot. The several samples at each spot were all within 2% of each other. The results were then calculated as a percentage of the center spot value.

The Cosina/Phoenix was as good as or better than any other lenses, to my eye, that I have used. Its overall exposures were slightly brighter than the Pentax made lenses. With and without the lens shade, at f3.5, the lens had slightly more than one quarter of one stop of darkening in the corners and an eighth of a stop half way to the corners. At f 4.0, the corner had lightened to less than a quarter of a stop. At f 5.6 and smaller, the corners and the area half way to the corners, lightened even more and were consistent. At f 4.0 and greater, I could measure that this lens, beyond the center, was just slightly darker than the Pentax made lenses, I could not see it with my naked eye. I might be able to use a deeper lens shade than the 39mm deep one I used, as

The Takumar was almost perfect. This lens has about one quarter of one stop darkening in the corners with the aperture wide open. By f 5.6 and smaller, the vignetting is reduced to four percent or less. I could not find any variation with or without the original hood.

The D-FA SMC WR was almost perfect also. This lens has less one quarter of one stop darkening in the corners with the aperture wide open. By f 4.0 and smaller, the vignetting is reduced to three percent or less. I could not find any variation with or without the original hood.

I have not posted any pictures. Twenty pictures of a uniform, gray, featureless field would be boring to almost all and a waste of storage space. My variability in the repetition of the tests is about three percent of luminosity. That is well less than one eighth of a stop.

The Cosina/Phoenix is very good. The two Pentax made lenses are small step better at the widest apertures, half way to the corner and in the corner. At all but the widest apertures, the Pentax made lenses are about 4-5% brighter than the Cosina half way to the corners and 5-7% in the corner, about 1/16 of a stop. Other than when the lenses are wide open, all the images are indistinguishable to my naked eye. These are all full frame 100mm macro lenses used on an APSc sensor. What else could you expect? With respect to vignetting, I could use these interchangeably.

Forum: Pentax SLR Lens Discussion 02-22-2016, 11:23 PM

Macro lens bake-off!
Posted By lmd91343

Replies: 43
Views: 5,836

This could be the worst or best zoom and/or macro ever made. But this test cannot judge that lens. I dropped the lens out of the testing for two reasons. The first is that the largest distance from the sensor/film plane of the camera to the copy stand baseboard can accommodate is 24.5 ". The shortest focal distance of the lens is 27.5". With two extra brackets and a QR plate I can extend the sensor to baseboard distance to 27.5". I could just barely bring the image into focus. I could not bring focus to slightly in front of the baseboard. To jeopardize the camera and lens for the test is not appropriate. So the Vivitar is out. I can describe its attributes and use.

The Vivitar is difficult to handle. It is large and heavy. The aperture ring is hard to find and read on a DSLR. The camera's flash bump is in the way. The tripod foot is small. The tripod ring lock screw is almost too small to use. The head is smaller than a dime. There are no click stops at 0* or 90* in the tripod ring for lens rotation. The aperture ring has positive feedback, clicking at every half stop. The zoom and focus rings have the right amount of resistance. The focus and and reproduction ratios are easy to read as they are exposed on the barrel when the focus ring is rotated, not in a small window. The lens comes with a matched factory hood. It is a joy to use where a front to back focus rail and moving the tripod would otherwise be required, just focus and zoom. This optic is great for flowers and the like outdoors.

Forum: Pentax SLR Lens Discussion 02-22-2016, 05:51 PM

Macro lens bake-off!
Posted By lmd91343

Replies: 43
Views: 5,836

I don't take photos where I am likely to get twigs and leaves entangled in a lens hood. My photos with a macro lens are much more controlled than that. I am paranoid about hurting my lenses. I almost always keep a good UV filter on my lens and a lens shade. The only time I don't is when I use macro lenses. I almost always use the hood. I figure the hood and the deeply recessed front element that allows me to drop the filter. That is why I am a bit upset with the new Pentax macro having only an inch of protection from the edge of the hood to the front element. I stick that macro lens right up to flowers and rocks. I am used to my Takumar which has 49mm of hood depth an 20mm of space in front of the front element totaling 69mm of protection.

Also I have never shot closer than 2:1 (.5X reprodution ratio) outdoors. that increases the closest focus distance by four inches!

I'll run a test this weekend with my camera lens and lens hood on the copy stand with cardboard 60* and 45* angles. I will check the angle that the light can be at without having the lens shade interfere at .5X and 1X reproduction ratio distances. Than I'll take a picture of that set up.

Forum: Pentax SLR Lens Discussion 02-21-2016, 10:09 PM

Macro lens bake-off!
Posted By lmd91343

Replies: 43
Views: 5,836

Interesting point. Sounds like an interesting test would be a set of quick tests with my copy stand, light stand, protractor, rulers and lens hoods. I have 49mm diameter lens hoods from 25-80mm deep. I'll have time in a couple of weeks. A nice extra test.

However, my past and most recent experience indicates that a lens hood does not get in the way.

The Takumar 100mm macro has a 20mm recessed front element, similar to that of the F 100mm macro. The Tak also has the dedicated 49mm deep lens hood labeled "TAKUMAR 100mm F4". Using the Cosina dedicated 1:1 supplemental lens the exact same closest focus distance as the DFA macro lens. Using the Tak with the supplemental lens and the hood, I have not had any easily overcome lighting issues at closest focus distance.

Fifty millimeter macro lenses have given me fits with self caused shadows at close focusing distances. I strive, like almost everyone to keep any non-image reflected light from the lens front element to reduce veiling flare.

Forum: Pentax SLR Lens Discussion 02-21-2016, 06:18 PM

Macro lens bake-off!
Posted By lmd91343

Replies: 43
Views: 5,836

The Cosina/Phoenix gives the appearance of cheapness, but it is not. It has a dedicated detachable 1:1 supplemental lens with its own case. The focus ring is thin, has little resistance, but no slack. It has autofocus, but no full time manual adjustment. The ring rotates about 315*.

The aperture ring has the "A" lock. It turns very easily with proper resistance and a click at every full f stop. There are two distance scales and two reproduction ratio scales, each with a unique color. All four wrap around the barrel helically and are exposed as the lens is focused. The index mark can be as far as an inch away from the scale. It is confusing to read. There is no DOF scale

My copy has no dedicated hood. There is no provision in the factory box for one. I use a Takumar 105mm hood. It attaches to the lens barrel so that it moves out as the lens is focused, always providing the same amount shade and physical protection to the front element at every focus distance.

What scale is what? What is it set to?

The Takumar is a thing of beauty to behold. The focus ring is very large, with appropriate resistance and no slack. It rotates about 315*. It is the easiest to focus manually. It is manual focus only. The distance scales are easily read from a window between the aperture and focus ring. The meter and foot scales are each different color. Is easier to use than the SMC WR, but not easy.

The aperture ring has positive clicks in the funky Takumar aperture ring pattern of full and half f stops clicking except for no half stops between f 4.0-5.6 and f 16-22.

As with the Cosina/Phoenix, the lens hood attaches to the lens barrel so that it moves out as the lens is focused more closely, always providing the same amount shade and physical protection to the recessed front element at every focus distance.

The dedicated shade can be reversed and slipped over the lens for storage or transport. The dedicated cap can be used over the reverse mounted lens hood or over the lens without the hood. The reproduction ratio scale is easily read at the end of the lens barrel, far removed from the distance scale.

The D-FA SMC WR macro lens is also a good looking lens. The focus ring has no slack and good resistance. It is small, but easy to find and turn. You can hear a slight noise as you turn it. It is an autofocus lens, with full time manual adjustment. It also rotates 315*. Both distance scales and the reproduction ratio scale are all displayed in a single window at the distal end of the lens. All three co-located scales are white. I wish they were each were a distinct color for easier reading. I would like to see the reproduction ratio scale removed to the distal end of the barrel like the Takumar. With the poor design of the reproduction ratio display, it is possible to have only one value exposed off-center in the window. This does not allow you to guess where the lens is set between two values. Is it one half or one third past the exposed value? What are the next values up and down? The problem gets worse as the magnification is greater, when the need to know is greater!

There is no aperture ring, so it cannot be used on a bellows. Therefore if you like this lens and if you have bellows, you need two macro lenses!

The area where this lens fails is with the lens shade. The hood attaches reversed for storage and protecting the lens. However when the lens is focused toward the closest focus and the inner barrel racks out, the hood does not move with it, providing decreasingly less shade and front element protection. At closest focus, the effective depth of the shade is less than one inch. It is as if the shade's primary function is to hide the ungainly looking inner barrel rather than shade and protect the front element.

What is the reproduction ratio? exactly?

Forum: Pentax SLR Lens Discussion 02-20-2016, 07:00 PM

Macro lens bake-off!
Posted By lmd91343

Replies: 43
Views: 5,836

I have endeavored to run a series of tests to check the quality of my new PENTAX-DFA SMC MACRO 1:2.8 100mm WR lens and check is IQ in relation to the three other long focus macro lenses I also own. Those other lenses are a Super-Multi-Coated-MACRO-TAKUMAR 1:4/100 and the Cosina made PHOENIX 100MM 1:3.5 MACRO AF. The Phoenix lens registers on my cameras as the "smc PENTAX-FA MACRO 100mm F3.5". My report of these tests are broken into the following sections:
• Description and Usability
• Vivitar 90-180 flat field zoom failure
• Vignetting
• Purple fringing
• Distortion and Decentering
• Resolution 1X Magnification
• Resolution .5X Magnification
• Test image .5X Magnification
• Test image .25X Magnification
• Far focus and bokeh test
• Color
• Other observations
• Conclusion

I will post a new section every day or two.

My basic premise before conducting these tests is that all the 100mm –ish macro lenses are excellent lenses. Before these tests, I have used and tested several, numbering about eight to ten.

All test images were capture with my Pentax K3 with AV exposure mode, attached either to my very rigid copy stand, Manfrotto 055 Pro Carbon Fiber tripod with a 468MG ball head and a ten pound weight suspended from the spider. A wireless remote was used to release the shutter. All focusing was done manually using focus peaking on the magnified setting. For resolution checking, the lens was set to the proper reproduction ratio and copy stand head was moved to achieve focus. All interior shots were taken with daylight color lights and light table. The images analyzed and presented are not post-processed in any manner other than resizing and jpeg conversion for web display.

Future macro tests I hope to do include testing the 50mm and 100mm macros with both extension tubes and tele-extenders. Also I wish to design and run an appropriate set of tests for the Vivitar 90-180mm flat field lens.

Forum: Pentax SLR Lens Discussion 02-03-2016, 03:00 PM

Macro lens bake-off!
Posted By lmd91343

Replies: 43
Views: 5,836

You bring up an important issue. What to use for a test target?

Obviously, I am not going to buy additional equipment to do this test. Therefore my results will be relative.

I've tried to set my laser printer to 1200dpi and printing PDFs of standard test charts. That produces moire patterns on some of the line pairs, with no line having a sharp edge, when magnified, due to the bumpiness of the smoothest paper.

I've tried using relatively new nickels and been able to examine some of the very small scratches on the smooth section of the coin to provide a sharp edge to examine. Not every nickel I tried worked. The engraved section is not appropriate. Also I don't recall trying it at better than .5X magnification.

I've looked at fine printing on clay coated paper. That may work. We will see.

I've thought of using a fine grained slide or negative with an image containing hard edges. If I managed to get past the irregular stain or grain pattern, what lens would I use to create that slide or negative? I think my best medium format lenses do not resolve as well as my 35mm macro lenses. If I use the lenses I am testing, what am I really testing? The resolving power of the sensor or the film?

I probably will use the calibration slide for my dedicated negative/slide scanner backlit by a small light table. At 1:1 with my new lens, an image with sharp lines remain sharp as the image is enlarged on the camera display to the point of pixelation.

My copy stand is quite rigid and has no noticeable vibration. The camera mount is perpendicular to the baseboard. The camera shutter release and any AF focusing will be one with a cable release. The calibration slide is in a special mount to keep it flat. I will place an extra 20 pounds iron weights on the baseboard for dampening. I will use it for the resolution, distortions, color cast, and macro picture image shots.

For short distance and long focus shots I will use my Manfrotto 055 CF, three section per leg,tripod with the center column down. The legs will be set on astro scope anti-vibration pads. A ten pound weight will be suspended from the spider. A cable release will be used for the shutter and AF. The head is a 468MGManfrotto, rated at 35 pounds.

For the inside shots I will check color balance for both the light table and overhead lighting. For outside shots, I will use AWB.

Forum: Pentax SLR Lens Discussion 02-01-2016, 07:30 PM

Macro lens bake-off!
Posted By lmd91343

Replies: 43
Views: 5,836

Ok I'll add a couple for each lens at the best aperture with the Rokunar. I'll also do the same with Vivitar at minimum, middle, and maximum extension. I will do this matching magnifications with the dedicated Close Up lens and extension tube. We can then compare them, apples to apples.

For fun I will run max magnification on each lens with the each TC at the best aperture.

Forum: Pentax SLR Lens Discussion 02-01-2016, 09:04 AM

Macro lens bake-off!
Posted By lmd91343

Replies: 43
Views: 5,836

Thank you for the encouragement.

As for the TC, to what end?

What are you contemplating? Use it with the macros at maximum magnification? Use it at long focus? Compare the macros to a 50mm with a teleconverter for macro use?

I have the Vivitar 7 element, 5 group macro focusing 2X teleconverter and a Rokunar 1.7X PZ/AF unit. I don't use them. I have only played with them on my telephoto and long zoom lenses. I don't know if these are good TCs or not. The Rokunar looks like the fabled Tamron.

I will have the set-up together for my testing including about 100 images in my plan. It would not be too hard to add a new parameter, but I want to be careful with what I add.

Forum: Pentax SLR Lens Discussion 02-01-2016, 07:53 AM

Macro lens bake-off!
Posted By lmd91343

Replies: 43
Views: 5,836

Thank you!

---------- Post added 02-01-16 at 07:35 AM ----------

I am lucky. I have a ~36mm AF/data coupled extension tube that should get the Tak to about .9X. I have the 1:1 adapter for the Cosina. I'll try that and the extension tube.

I have no idea about the magnification of the Vivitar zoom other than the engraved values. Who knows the accuracy of those. I'll need to experiment with the ext tube and use a ruler!

Your point about the Vivitar 135 is a good one. What most people use for high magnification photos does not require either flat field focusing or 1:1 magnification.

Forum: Pentax SLR Lens Discussion 01-30-2016, 06:12 PM

Macro lens bake-off!
Posted By lmd91343

Replies: 43
Views: 5,836

Macro lens bake-off!

I have just acquired a SMC Pentax-D FA 100mm F2.8 Macro WR macro lens. It should arrive by Monday night via UPS. Currently I also have a Super-Multi-Coated MACRO-TAKUMAR 100mm F4 Macro. My second current macro lens is the Cosina 100mm F3.5 MC Makro Lens, marketed as a Phoenix. My last long macro is the Vivitar Series 1 90-180mm f 4.5 Flat Field Lens.

I intend to run a series of tests on the four lenses, with the intent of selling off the Cosina and testing my new Pentax. My tests will include the following for each lens at every full f-stop:
... From a copy stand:
...... o Paper target with text and resolution chart at 1:2 magnification.
...... o Paper target with text and resolution chart at 1:1 magnification.
...... o Color chart and gray card.
... On a tripod:
...... o Flowers and plants outside.
...... o A brick wall (maybe).
...... o Decentering test (new only)

All shots will be focus bracketed, use the MUP option, and be focused and tripped with a cable release. I'll post pictures and thoughts when complete. I know that I am not testing a species of lens, but rather a specimen of each of the species.

HAVE I MISSED ANYTHING?

Previous testing:
Years ago, before joining this group and converting my K10 to IR, I ran a similar bake-off with a manual focus version of the Cosina, the Vivitar Series 1 "Bokina" (tokina) 90mm F2.5 Macro Lens (with the 2X attachment that fastened to the back of the lens), and the Vivitar Series 1 (Kiron - 22xxxxx) 105mm f2.5 (100mm f2.8) Macro Lens.

The results from that test was I found that all were very sharp. The Takumar was the sharpest and had a feeling or rendering that I liked best. The 90mm Vivitar was the second sharpest, with a cooler color. Bringing up the rear as the least sharp was the 105mm Vivitar. It was still very sharp. I could have been happy with any. I stopped testing the Vivitar zoom part way thru. It was very sharp, however I had no intention of selling it and it was too big and heavy to use because of my back at the time. I sold the Cosina, Vivitar 90, and Vivitar 105.

My current *BELIEF* based on my limited experience, with only ten (including Canon brand) ~100mm dedicated macro lenses is that they are all pretty sharp and that differentiations should be based on other criteria such as OOF, bokeh, ease of use, weight, brightness, ... . We will see what happens.

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