Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
02-27-2016, 06:22 PM - 1 Like   #31
Site Supporter
Site Supporter




Join Date: Jul 2009
Location: Los Angeles, CA USA
Photos: Gallery | Albums
Posts: 666
Original Poster
Results: Test image .5X Magnification

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.



02-28-2016, 02:09 PM   #32
Pentaxian




Join Date: Jan 2013
Location: Near Vienna, Austria
Photos: Gallery
Posts: 1,037
Amazing job!
In these last series of shots, I'm under the impression that the newer lenses have better overall contrast than the Takumar. Is that correct?
02-28-2016, 03:30 PM   #33
Site Supporter
Site Supporter




Join Date: Jul 2009
Location: Los Angeles, CA USA
Photos: Gallery | Albums
Posts: 666
Original Poster
QuoteOriginally posted by wkraus Quote
Amazing job!
In these last series of shots, I'm under the impression that the newer lenses have better overall contrast than the Takumar. Is that correct?
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.

Last edited by lmd91343; 02-28-2016 at 11:42 PM. Reason: Spelling
02-28-2016, 11:11 PM - 2 Likes   #34
Site Supporter
Site Supporter




Join Date: Jul 2009
Location: Los Angeles, CA USA
Photos: Gallery | Albums
Posts: 666
Original Poster
Results: Test image .25X Magnification

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.





02-29-2016, 12:38 AM   #35
New Member




Join Date: Feb 2016
Location: Illinois
Posts: 12
Wow, thank you for sharing these!
02-29-2016, 09:20 AM   #36
Pentaxian




Join Date: Jan 2013
Location: Near Vienna, Austria
Photos: Gallery
Posts: 1,037
QuoteOriginally posted by lmd91343 Quote
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.
Thanks for your detailed reply above. Judging from the last set, the Takumar might indeed have a little less contrast, but on the whole it holds up amazingly well against the more modern lenses. What I would like to know: how much closer did you have to go with the newer lenses for the same reproduction ratio? In other words, how well do they keep their focal length at closer distances?
03-01-2016, 04:27 PM   #37
Site Supporter
Site Supporter




Join Date: Jul 2009
Location: Los Angeles, CA USA
Photos: Gallery | Albums
Posts: 666
Original Poster
Results: Color

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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
03-01-2016, 08:47 PM - 1 Like   #38
Site Supporter
Site Supporter




Join Date: Jul 2009
Location: Los Angeles, CA USA
Photos: Gallery | Albums
Posts: 666
Original Poster
QuoteOriginally posted by wkraus Quote
Thanks for your detailed reply above. Judging from the last set, the Takumar might indeed have a little less contrast, but on the whole it holds up amazingly well against the more modern lenses. What I would like to know: how much closer did you have to go with the newer lenses for the same reproduction ratio? In other words, how well do they keep their focal length at closer distances?
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'

03-02-2016, 03:13 PM   #39
Pentaxian




Join Date: Jan 2013
Location: Near Vienna, Austria
Photos: Gallery
Posts: 1,037
QuoteOriginally posted by lmd91343 Quote
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'
Exactly! Very interesting, thanks so much.
03-02-2016, 03:57 PM   #40
Site Supporter
Site Supporter




Join Date: Jul 2009
Location: Los Angeles, CA USA
Photos: Gallery | Albums
Posts: 666
Original Poster
QuoteOriginally posted by wkraus Quote
Exactly! Very interesting, thanks so much.
What does this information mean in terms of changing lens design?

Thanks!
03-03-2016, 02:41 AM   #41
Pentaxian




Join Date: Jan 2013
Location: Near Vienna, Austria
Photos: Gallery
Posts: 1,037
QuoteOriginally posted by lmd91343 Quote
What does this information mean in terms of changing lens design?

Thanks!
That the newer lenses change their focal length as you focus closer. This is the case with many modern lens designs. IF constructions and most newer macro lenses essentially zoom rather then extend to focus or employ a combination of both. I'm not sure how to compute the effective focal length from your data. According to Photozone, the Canon EF 100mm f/2.8 USM L IS Macro has a focal length of only 75mm at MFD. The D-FA seems to behave similarly but perhaps to a lesser degree.
03-04-2016, 02:38 PM - 1 Like   #42
Site Supporter
Site Supporter




Join Date: Jul 2009
Location: Los Angeles, CA USA
Photos: Gallery | Albums
Posts: 666
Original Poster
Results: Other observations

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.


03-07-2016, 04:02 PM - 2 Likes   #43
Site Supporter
Site Supporter




Join Date: Jul 2009
Location: Los Angeles, CA USA
Photos: Gallery | Albums
Posts: 666
Original Poster
Results: Conclusion

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!
03-08-2016, 08:42 AM   #44
New Member




Join Date: Feb 2016
Location: Illinois
Posts: 12
Great write up!
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
100mm, bokina, calibration, camera, chart, cosina, extension, focus, hood, k-mount, lens, lenses, macro, macro lens, magnification, pentax lens, series, slr lens, takumar, test, tokina, tripod, tube, vivitar
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Macro Couple of new macro shots to show off Paleo Pete Post Your Photos! 8 08-01-2014 04:57 PM
Macro Showing off my new Macro lens NicoleC Post Your Photos! 3 12-29-2013 06:23 AM
Show off your Macro Lens dj_saunter Pentax SLR Lens Discussion 30 09-16-2010 06:13 PM
In and around the Chive Patch... dusting off the macro lens SCGushue Post Your Photos! 16 06-11-2008 08:55 PM
Statues, Trees and Buildings and a Smile (56k.. go bake a cake :)) quickpix Post Your Photos! 2 01-30-2008 04:51 AM



All times are GMT -7. The time now is 11:17 PM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top