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Forum: Lens Clubs
08-14-2023, 10:04 AM
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One more w/ Q and No. 3 FE lens. This is only w/ minor exposure adjustment to the Q's B&W jpg.
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Forum: Lens Clubs
08-11-2023, 06:53 PM
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Pentax Q, No. 3 Fisheye, and Fisheye Hemi Software.
I like this fisheye les/camera combo, as it gives me a very portable, very wide angle, and moderate fisheye effect--so it is very useful for general photography. And Fisheye Hemi completes the package. Two shots taken in MOMA in NYC. One is partially defished, the other totally so. In both cases did some sharpening w/ Topaz Sharpen AI.
It may be of interest to see the images before any pp (beyond camera raw). I have included them. Considering the central angle (fisheye lens has considerably wider angle at the periphery), fisheye hemi loses none of the image (in the horizontal dimension--clearly not the case in the second image) if the image is totally defished--i.e., it makes the angle of view essentially uniform. BTW I use the canvas option in PS to add margins to the image, so when defished it is rectalinear in one dimension.
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Forum: Photographic Technique
08-05-2023, 09:22 PM
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Forum: Photographic Technique
08-05-2023, 09:53 PM
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Perhaps the simplest argument is: try it. That is the great thing about digital.
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Forum: Photographic Technique
08-05-2023, 11:16 AM
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This is neither my understanding or experience. Assuming one is in the iso-invariant region, then given the following scenario:
shot at the same shutter speed and f-stop, but
1. at a lower iso (e.g., 2 stops underexposed)
versus
2. shot at higher iso (0 stops underexposed)
the two shots after pp will look the same (identical!) except there is greater likelihood the highest exposure areas will be overexposed—and not recoverable—in scenario 2.
I face this in most of my theater photography. I am limited in shutter speed (to avoid excessive motion blur) and limited in f-stop (I want sufficient depth of field or the lens is already fully open). So that may often means (e.g. with a 35 mm lens) I want f/4 and 1/30s, but that may require iso 1600 to be properly exposed.
For my Pentax K-5 I rather shoot at iso 400 and increase exposure in post. This gives me less likelihood of blowing highlights and otherwise they are identical. (And I have done the comparison of the two scenarios many times.)
With my Nikon D-700, it is iso-invariant above iso 800, so I use iso 800.
Actually one could have even more margin for the highlights, but in reviewing the shot, more than 2 stop underexposure becomes problematic, and there is a limit to the exposure increase in camera raw—believe it is 4 stops, and thus 2 stop underexposure is for me a safer lower iso.
---------- Post added 08-05-23 at 11:24 AM ----------
BTW, this makes exposure very simple. For the camera-lens combo that is limited in exposure (a min shutter speed and max f-stop), I often don't even take exposure readings. As i know the theater lighting well enough to know I will not be overexposed.
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Forum: Film SLRs and Compact Film Cameras
02-22-2018, 01:11 AM
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On a clear sunny day with the sun fairly high in the sky, if you meter the blue sky, but not near the sun, your reading will be the sunny 16 rule (1/iso in sec at f/16--e.g., at iso 100, it should be f/16 at 1/100 sec, or f/11 at 1/200 sec, etc.). This method (metering blue sky) is both reliable and easy to do.
If you don't get this result adjust the iso (ASA) number so it does give you this result. (E.g., if setting iso = 100, the camera says 1/400 sec at f/16, that means you should divide the iso by 4--i.e., whatever the film iso is, set the camera iso 1/4 of that value.
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Forum: Pentax DSLR Discussion
05-05-2022, 07:35 PM
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My Q in work clothes (the 6x12 optical finder has a 120 degree Horizontal FOV).
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Forum: Digital Processing, Software, and Printing
11-12-2020, 09:33 PM
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For me the printing process is (now) the more creative part of my photography. The choices for a print are not the same as looking at the image on the screen, and there is the question what kind of paper is best. I also have the option to print an image and hang it up so I see it all the time, and thus decide if it has staying power.
For about 10 years I used a small inexpensive (dye) ink jet printer typically printing 8”x whatever” and now I have a larger 13”x whatever (pigment) ink jet printer. Either way the results are the same—as regards the process and the results—except of course the print size and whether a paying customer would accept a dye based print.
Actually coming from film, where prints were done by someone else, the biggest change is:
1. I am doing my own printing
2. for theater photography I can take 1000’s images of a play, versus maybe a 100 images with film.
That is about it—otherwise film and digital are about the same for me. So printing is a big deal for me.
Even if you use labs to print, first printing small you can make the artistic choices, and then you have a print to check the lab’s result. In my case the lab. was my university print shop and I could compare test prints, before having them print large—not sure how it works when using a commercial lab.
If you are not sure you can invest in a small dye based printer as I did, and see. I started with a $70. reconditioned Epson Clara ink set printer, and the results were (for me/effectively) indistinguishable from the Epson large professional pigment based printer. I presume the situation is similar w/ Canon printers.
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Forum: Digital Processing, Software, and Printing
06-15-2022, 09:12 PM
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The comments (posts) seem to center on two areas: 1. software is useful but problematic as it/they are altering the images and 2. like anything you need to take care and check it.
These are actually very divergent as there is a difference between (for example) sharpening too much and getting halos and sharpening and getting a sixth toe.
One can know how usual sharpening works and thus what to look for, but one does not know what the software in question does. That is a big difference. For all I know it will replace eyelashes with swastikas, but if I don't check everywhere at the pixel level I cannot be sure!
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Forum: General Talk
06-08-2022, 10:12 AM
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I also like PAPILIO 6.5x21. It is not waterproof AFAIK, and likely not good in dusk/dawn.
Likely highly subjective, but I find 8x to be too strong and not usable, and for what its worth, my ability to take long exposure hand held is quite good.
Actually I like Fuji GlimpZ 5x21 for canoeing, but also not waterproof.
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Forum: Troubleshooting and Beginner Help
05-30-2022, 08:43 AM
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You can in post set a reasonable WB from the white of the eye, or sometimes any white/gray area in the image. (Gray and white being the same thing, just white has the higher/highest reflectance in the scene.) As noted earlier you don't usually want to reduce the desired effect of sunset, stage lighting, etc. by setting WB to make white/gray look white/gray.
Also with K-5 thru K-1 (no accelerator), the sensor/in camera processing has DR that drops 1 stop for every doubling of iso, after roughly iso 200~400, so instead of - ev you may want to simply leave camera at low iso** and adjust exposure in post--this prevents overexposure and the darks are as good as if one used the higher iso w/o adjusting in post (for me the biggest advantage of using raw). Lots of sites have DR vs exposure for most/all the higher end digital cameras.
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** My bad, this only works where you keep the measured exposure at high iso, and then reduce the iso for the shot. For me in theatre photography I don't use light meter, I set low shutter speed and smallish aperture (e.g., 1/30s and f/4), and low iso.
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Forum: Pentax SLR Lens Discussion
05-21-2022, 07:38 AM
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Once in the diffraction region every 2 stop smaller aperture (opening) reduces resolution by 1/2, and w/ higher resolution sensor at f/22 you may (as guess-estimates) 1/2 ~ 1/4 the expected resolution, and in macro regime the effective aperture is much smaller, and it depends on the distance, but very possibly you may have 1/4 ~ 1/8 the expected resolution. I suggest you read a book on macro photography that discusses this stuff. The "manual of close up photography" by Lefkowitz (1979) is the best source I have ever read.
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Forum: Photographic Technique
05-19-2022, 11:10 AM
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this reminds one of pre-exposure or post-exposure to cause exposure that is below the threshold for film to become visible, and it does also lead to reduction in contrast (but that is not why you do it and it is a undesirable aspect (you increase DR and thus reduce contrast). One exposes about 3 to 5 stops less than the indicated exposure. (Slide film typically 3 or 4 stops, B&W/color negative 4 or 5 stops.)
With digital I don't think it works as the issue is not a threshold but increasing noise in the shadows, but I am not sure. In any event I gather this is solely about contrast.
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Forum: Troubleshooting and Beginner Help
05-12-2022, 12:07 AM
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Going beyond your question, there is another possibility. This applies to Pentax DSLRs from K-5 to K-1, which are basically "isoless" [for each doubling of iso, the DR is reduced by 1 stop]. Take the picture at the:
-- desired shutter speed (to avoid too much motion blur)
-- a desired f-stop (to avoid too little DOF)
-- and a desirable low iso
thus taking the shot with you might think less light than optimum (for the shadows), but not so. By not increasing the iso, you:
(1) avoid possibly blowing the highlights, and
(2) as regards noise in the shadows, there will be no more noise than if you increased the iso.
But to answer your question: two stops is doubling (or halving the aperture), and thus one stop is about 1.5 times (or 1.5 divide into) the aperture (or simply 3/2 or 2/3). If you remember any f-stop you know the others. So for example f/4. Two stops is f/8 or f/2, and 1 stop is f/4 x 3/2 = f/6 (close enough to f/5.6) or 4 x 2/3 = 8/3 ~ f/3 (close enough to f/2.8). Actually the f-stop progression is not mathematically correct, as if so they would all be related by 1.414.. [square root of 2], or 1/1.414, and they aren't. (So there is no rule to remember those intermediate f-stops. f/1, f/2, f/4, f/8, etc. are fine, but not the in between ones.)
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Forum: Pentax SLR Lens Discussion
05-17-2022, 09:14 PM
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I don't have the lens, but the performance/halo are not IMO excessive for an inexpensive lens at or near full open. (Or for an older fast expensive lens at/near wide open.) I suggest trying it at f/11. It may be fine there, and if so having two personalities is useful. I would treat it as positive, and use the lens in situation where the look would be desirable (e.g., many colorful lights/portraits/etc. where the softening/fog is attractive).
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Forum: Canon, Nikon, Sony, and Other Camera Brands
05-14-2022, 02:23 PM
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I would suggest a Nikon D700. I have two of them I use for my theatre photography, although my work is not challenging for the AF, I have heard it is quite good in tracking. And as you are considering the 4S, this is professional build but smaller/less expensive--$400 for a good condition one at KEH or B&H.
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Forum: Digital Processing, Software, and Printing
05-13-2022, 04:34 PM
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On my Epson V600 the leading edge of the glass is 40 cm from the hinge. But this is with the lid raised up. I don't understand fully your question. With the lid parallel to the glass it would be closed, but still the same 40 cm (or very close to it).
Oh, you want the clearance between the lid and glass, right? If the lid is parallel to the glass it is closed so how do I measure it. Obviously I am missing something!!
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Forum: Vintage Cameras and Equipment
02-23-2022, 10:14 PM
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51 mm FL seems odd/uncommon. I would have thought it would be rounded to 50 mm.
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Forum: Photo Critique
02-18-2022, 05:55 PM
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I did the following changes:
1. adjust white balance--it was slightly greenish
2. did midtone unsharp mask (believe it's equivalent is called clarity) in Photoshop
3 did a sharpening--used Topaz Sharpen AI
If these are useful the equivalent can be done in other pp software.
BTW it is a very good image.
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Forum: Product Suggestions and Feedback
02-12-2022, 06:45 PM
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I don't think it is an obvious conclusion that a dedicated macro is best. In the field, a zoom has the advantage of allowing changing the magniifcation (image size) w/o moving the camera, and as macro is generally done from a tripod this is a big deal. If the magnification is generally only moderate (about 1/3 or less) a close focusing zoom may work much better. This is likely why the Vivitar series 1 70-210 mm lens was so popular--it having a close up ability and also a good image. Ultimate image quality is less but that is not likely an issue. If you want to focus somewhat closer a proper supplementary close up lens (screw on filter) would work well enough. Likely about a +2 if using something like the 70-210 mm Vivitar.The FA 28-70 f/4 might be an inexpensive fine lens w/ something like a +2 or +3 diopter. A 2 element diopter is probably a good idea--e.g. in 52 mm diameter a used Nikon 3T (1.5 diopter) or 4T (2.9 diopter). The Tamron Adaptall 35-80 mm lens (01A) is very good and close focusing--except it flares badly and thus not good with lights/sun in the image (unfortunately I found unusable w/ stage lighting).
Incidentally, I have all these lenses, as well as dedicated macro lenses (55 mm and 90 mm in Nikon F mount, and 50 mm and 105 mm in Pentax K) , and if I was planning on in the field macro work I would take the zoom + diopter approach. Even in the studio/home it is much easier.
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Forum: Digital Processing, Software, and Printing
02-07-2022, 11:58 AM
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Also suggest you accumulate several images and then take small slice from each and combine in a single file and print it. Then adjust/pp each image and repeat combining slices from each again. When they are good, then print them individually. This save ink and paper.
This assumes some pp, but basically just an exposure adjustment (and sometimes a white balance) should generally get you a pleasing result. Biasing the camera exposure to obtain a good exposure and good print would work if the dynamic range is not too large--e.g., what we did with slide film. (But this is going forward for future images.)
And of course reduce your screen brightness as everyone suggested. This can be done reasonably well w/o other software. (This is how I did it.)
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Forum: Pentax Camera and Field Accessories
12-31-2021, 12:46 PM
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Did you look in this site's my activity/post or threads? I should think the link to the recommendation would be there, if it was specifcially to answer a post/thread of yours. My bad, I see you already did this.
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Forum: Pentax SLR Lens Discussion
04-15-2019, 08:42 PM
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Of course it depends on what focal length you will find works for your eye. And that comes from looking a images taken with various focal lengths and your own usage/experience.* But since you asked:
-- I found 35mm was fine with film, for landscapes over maybe 3~4 decades, and only with digital did I gradually go wider and wider, to the point where now maybe 1/3 of my landscapes use fisheye lenses.
-- But I think it is related to digital and the control one has versus film where (for me and most of us) it was the slide, or the prints from the store that did the developing. With prints I often collaged them by pasting them on a board, which was in some ways more arty/rewarding than digital processing.
-- So I would say either the Pentax Super (or SMC) Takumar 28 mm f/3.5 or 35 mm f/3.5 ** are good choices (I have both of them, and they are excellent, although the 35mm f/3.5 is considered by many to be one of the best lenses, it really is unimportant--they are both very good.) Neither of mine are SMC (multi coated) and they do fine (although I always use a lens hood--actually with all my lenses--SMC or not).
-- But the 28 mm is quite bit wider, and thus is more difficult to use (near far relationships become more critical and w/o them the pictures can look flat), thus I would start with the 35 mm f/3.5. Although there are many good lenses I think sticking w/ Pentax for this makes good sense. Also Pentax lenses generally age very well!
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* I actually went through Ansel Adams book (Camera and Lens) and noted for each picture what the equivalent 35mm focal length it was, and a significant number were close to 35mm, and perhaps surprisingly very few were wider.
** Late Super Takumar 35mm f/3.5 lenses apparently were SMC, but not stated as such.
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Forum: Pentax SLR Lens Discussion
10-27-2021, 08:35 AM
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The one optical test I do w/ all my lenses is to test for decentering. I photograph a US air force 1951 test chart (print one out, you should be able to find one if you google it) from tripod in MF and aligned w/ the chart. Set focus and the with lens wide open swing camera so chart is in corners and center (so 5 images) and then open images and compare resolution. By identifying the relative resolution in the 4 corners, and center, you can see if the image plane of focus is very flat or not and whether any corner is very different in resolution (decentered).
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Forum: General Talk
10-17-2021, 10:58 AM
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