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03-15-2014, 03:22 PM   #1
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Adapted telephoto M42 Lenses - PF/CA Problems..Solutions?

Adapted telephoto M42 Lenses - PF/CA Problems..Solutions?

Like many of us, I have a number of great old M42 Taks. But it seems if there is ever a problem using them on the Q, its PF/CA.

Besides the usual Pre-shot stop-down etc., I still end up with shots I like - other than the PF/CA.

I have tried some of the PostProcessing 'tricks' - magenta saturation adjustment, GIMPs Fix-CA plugin, etc. and I can't seem to get them to work.

So, I am asking for advice from our more experienced members: How do you deal with PF/CA? (Other than buying a DA* 300..:>)?

I've attached one example - toy Swans with a tree-branch background - loaded with CA. This was a SMCT M42 135/3.5 - stopped down one click. I like the lens a lot. I like the color, contrast, and sharpness. Often, it works great (Example - 2nd Bird-shot - except for my focus/hand-held problems)

So how do you handle PF/CA? Any and all advice, suggestions, techniques, references (URL - whatever) greatly appreciated!

If you wish, I'd love to see samples of the 'toy swan' with your technique(s) applied...

P.S. - Adam/Admins - even though this can relate to PostProcessing and Software - its such a problem with adapted lenses on the Q I placed the post here. Hopefully OK..

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03-15-2014, 04:47 PM   #2
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Yes buying a lens with some UD glass will improve the secondary spectrum. How about this edit.
03-15-2014, 05:05 PM   #3
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QuoteOriginally posted by clicksworth Quote
Yes buying a lens with some UD glass will improve the secondary spectrum. How about this edit.
Looks great! But pardon my ignorance, how did you do it? Whats 'UD Glass'? Thanks!
03-15-2014, 05:33 PM   #4
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QuoteOriginally posted by cahudson42 Quote
Looks great! But pardon my ignorance, how did you do it? Whats 'UD Glass'? Thanks!
UD is one name for the low-dispersion glass that is necessary for good long lenses.
That edit was done in Gimp but other programs will do the same. The fringing is mostly cyan and red, so I used the Hue/Saturation function to shift those colours toward green and desaturated them a bit so that they blend with the leaves. Shifting the red however messes up the orange of the beaks. To fix that, make a second bottom layer with original colours, then erase through the top modified layer only over the beaks. The process isn't suited to all photos depending on what colours are in them.

03-15-2014, 09:41 PM   #5
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QuoteOriginally posted by clicksworth Quote
UD is one name for the low-dispersion glass that is necessary for good long lenses.
That edit was done in Gimp but other programs will do the same. The fringing is mostly cyan and red, so I used the Hue/Saturation function to shift those colours toward green and desaturated them a bit so that they blend with the leaves. Shifting the red however messes up the orange of the beaks. To fix that, make a second bottom layer with original colours, then erase through the top modified layer only over the beaks. The process isn't suited to all photos depending on what colours are in them.
Thanks for the explanation. Really helpful to me. Took your saturation idea and tried it in LightZone. Used eyedropper to select green and magenta fringing, reduced saturation to zero. Was able to do that multiple times for different CA shades w/o seemingly effecting beaks etc. Bit of a pita, but if it salvages shots with my Tak, OK!

More ideas anyone?
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03-18-2014, 01:33 AM - 1 Like   #6
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Trying to get the best out of the M42 is something that concerns me. I like the old glass and enjoy using it. I have been experimenting with uv-ir cut filters wondering if they help and so did the thread; https://www.pentaxforums.com/forums/136-pentax-q/248682-fringe-killing-q-2.html. The resulting improvement with the filter is reasonably subtle but I feel enough to habitually have one on like we did in the old film days with uv filters.

I have always found that fringing is variable , sometimes an image comes out free and sometimes it is rainbows. So I did some testing today to try and get some objective results.Fringing seems to be worst in slightly oof areas so the first test was to clarify this. But as you can see fringing was there right throughout although changing colour at the focus point. The focus test also confirmed what I suspected-- that the blue end of the spectrum fringed when focussing too near and the red end flared when focussing too far. Or put another way- oof areas beyond the subject fringe bluish and oof areas nearer than the subject fringe red. The filter seems more effective at the red end. I suspect the lens glass is already stopping the uv. Remember that the filter is stopping light that is invisible to us so the cooling of the images taken with the filter is the removal of infrared rays.

The second test was a simple fstop comparison and also a filter comparison. We have always known that stopping down helps and I think when fringing is an issue it would be an option to push this lens out to f11 which is normally considered diffraction country. F11 with filter appears to be the sweet spot with this lens for this situation.

The lens used here is the tele takumar 1;5.6 200mm preset, a lovely old piece. Remember that the image is one designed to maximize CA. I took a 400 pixel crop from the range of images and pasted them together and resized for here.

I feel another test worth doing is a comparison of exposure , ie does underexposure help or make things worse.
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03-18-2014, 07:35 AM   #7
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I am a bit hardline on this.

The Q got a bad rep precisely because one of the reasons was that initially, many early samples were of Q+old/questionable glass.
Yes, it gave the reach, but that novelty wore off fast (esp for non-fans).
Hazy shots with reach, but lacking resolution, contrast and PF

The pixel density is too punishing on some legacy lenses, and we just got to accept that.

Look to orphaned Canon FD or something else for good fast lenses for cheap options.
Frankly, M42 is a bit too old in coatings, aspherical elements technology (none) and modern lens designs (which telephotos and UWAs have benefited more than other focal lengths)

Sadly, almost all the better Pentax 135mm PF badly on the Q too. (K135; FA135; )
They do have the resolution though.

For PF, I would try the easy way duplicating a layer and desaturating the magenta.
If that does not affect the photo, thats all that I will do.
If it does, I will use a layer mask and paint in the PF area.

Last edited by pinholecam; 03-18-2014 at 04:41 PM.
03-18-2014, 09:14 AM   #8
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QuoteOriginally posted by pinholecam Quote
......
Look to orphaned Canon FD or something else for good fast lenses for cheap options.....
Interesting observation. Thanks! Any FD suggestions around 135mm? (I admittedly know nothing about Canon Lens designations, ages, capabilities...)

---------- Post added 03-18-14 at 09:19 AM ----------

QuoteOriginally posted by GUB Quote
...... I have been experimenting with uv-ir cut filters wondering if they help and so did the thread; https://www.pentaxforums.com/forums/136-pentax-q/248682-fringe-killing-q-2.html. The resulting improvement with the filter is reasonably subtle but I feel enough to habitually have one on like we did in the old film days with uv filters.......
I have always found that fringing is variable , sometimes an image comes out free and sometimes it is rainbows. So I did some testing today to try and get some objective results.Fringing seems to be worst in slightly oof areas so the first test was to clarify this. But as you can see fringing was there right throughout although changing colour at the focus point. The focus test also confirmed what I suspected-- that the blue end of the spectrum fringed when focussing too near and the red end flared when focussing too far. Or put another way- oof areas beyond the subject fringe bluish and oof areas nearer than the subject fringe red. The filter seems more effective at the red end. I suspect the lens glass is already stopping the uv. Remember that the filter is stopping light that is invisible to us so the cooling of the images taken with the filter is the removal of infrared rays.......
Interesting, thorough, and educational (to me for sure) post. Thanks! May I ask - with the uv-ir cut filter, was there a hood as well? Not sure - but when I look at the comparisons I think I see a contrast loss compared to without it. Or is it an illusion?

03-18-2014, 10:10 AM   #9
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QuoteOriginally posted by cahudson42 Quote
I think I see a contrast loss compared to without it. Or is it an illusion?
Same hood on each. I can see what you mean, I wonder if it is the loss one expects putting a filter in the image path or is it that perhaps thatthe image has lost the hottest parts of the red and that has flattened the look.
03-18-2014, 04:37 PM   #10
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QuoteOriginally posted by cahudson42 Quote
Interesting observation. Thanks! Any FD suggestions around 135mm? (I admittedly know nothing about Canon Lens designations, ages, capabilities...)[COLOR="Silver"]

There are quite a few old 100mm f2.8 (macro) from Pentax too and worth a look.
This will provide super macro capability with the Q as well as become a pseudo 550mm f2.8.
Macro lenses as well as 100mm lenses are generally good optically too and likely stand up to the high pixel density of the Q.
Furthermore, you can afford to stop down to f4 to get better optically w/o reaching diffraction on the small sensor.

Otherwise, there is the famous Nikon 105/2.5 Ais (The Afghan girl lens - from that portrait shot by Steve McCurry)
Cheap because it was in production for so many years, often ignored for AF choices nowadays.

Canon FD, try the 135/2.5 or 135/2.8.
Try Keh, or some place you are familiar with.
Here are some keh links for an idea of their cost (low)
http://www.keh.com/camera/Canon-Manual-Focus-Fixed-Focal-Length-Lenses/1/sku...10400243N?r=FE
http://www.keh.com/camera/Canon-Manual-Focus-Fixed-Focal-Length-Lenses/1/sku...10400243N?r=FE

My personal experience with the Canon FD lenses are the 135/2 and 100/2.
These have PF too used wide open.
I don't use them on a Q though.
Canon lenses have a 'cleaner, brighter, cooler' look to them, so be aware of that.
03-18-2014, 05:08 PM   #11
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My goal was in trying to extract the best possible image from adapted lenses on the Q, and so I quickly gave up on trying to use older lenses.
@pinholecam has some good suggestions above.
There have been some samples shown in the adapted lens thread that do show promise, you can look through the thread to see which ones are good.
@GUB has been posting some nice samples with the 110 lenses also.
03-19-2014, 12:03 AM   #12
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QuoteOriginally posted by GUB Quote
....I have always found that fringing is variable , sometimes an image comes out free and sometimes it is rainbows. So I did some testing today to try and get some objective results.Fringing seems to be worst in slightly oof areas so the first test was to clarify this. But as you can see fringing was there right throughout although changing colour at the focus point. The focus test also confirmed what I suspected-- that the blue end of the spectrum fringed when focussing too near and the red end flared when focussing too far. Or put another way- oof areas beyond the subject fringe bluish and oof areas nearer than the subject fringe red..

The lens used here is the tele takumar 1;5.6 200mm preset, a lovely old piece. Remember that the image is one designed to maximize CA. I took a 400 pixel crop from the range of images and pasted them together and resized for here.
.
I should have added how much your post has helped me to at least understand what is happening with CA vs. focus. I also have the nice PS 200mm F5,6 old Tak, and did notice on some bird shots purple fringing on the beak when I was slightly out of focus - that went away in focus (adapted lens thread). Now looking at other shots, I see how the CA color shifts between too near and too far... Understanding is at least the necessary first step in dealing with it. Thanks!
03-19-2014, 12:38 AM   #13
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QuoteOriginally posted by cahudson42 Quote
Understanding is at least the necessary first step in dealing with it. Thanks!
Thanks for that. That is exactly why I go out and find the worst possible situation for the lens to experiment. People should not use this image as proof the lens is not good enough. I actually thought the 200 stood up to this image of sticks against the sky very well.
The demonstration image at the top is wide open at f5.6 and I think the CA is quite muted. At 200mm my DAL 55-300 would be wide open and a soft mush. The 01 8mm lens would have CAed in this situation albeit at the margins.
03-19-2014, 01:49 PM   #14
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M42 100mm F4.0 SMC Macro Tak

QuoteOriginally posted by pinholecam Quote
There are quite a few old 100mm f2.8 (macro) from Pentax too and worth a look....
Macro lenses as well as 100mm lenses are generally good optically too and likely stand up to the high pixel density of the Q.
Otherwise, there is the famous Nikon 105/2.5 Ais,,,,,,
Canon FD, try the 135/2.5 or 135/2.8.....
My personal experience with the Canon FD lenses are the 135/2 and 100/2....
Suggestions appreciated pinholecam! I like the M42s in part because they can be used on both my K-01 and the Q., though if the improvement would be substantial, the low cost would seem to justify the Nikon/Canon for the Q alone...

Dug out my M42 100mm 4.0 SMC Macro Tak that I usually use on the K-01, and went back to the Toy Swans with it and Q. Two shots following, the first at 4.0, the second at 5.6. (No PP, JPG cropped a bit right off the Q) Seems a bit of an improvement over the 135mm, at 5.6 at least.

In your opinion and experience, would I expect to do better with the Canons and or Nikon? Are they 'more modern' designs you mentioned? (aspherical, etc.)

Thoughts/suggestions always appreciated!.
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03-19-2014, 04:00 PM   #15
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QuoteOriginally posted by cahudson42 Quote
Suggestions appreciated pinholecam! I like the M42s in part because they can be used on both my K-01 and the Q., though if the improvement would be substantial, the low cost would seem to justify the Nikon/Canon for the Q alone...

Dug out my M42 100mm 4.0 SMC Macro Tak that I usually use on the K-01, and went back to the Toy Swans with it and Q. Two shots following, the first at 4.0, the second at 5.6. (No PP, JPG cropped a bit right off the Q) Seems a bit of an improvement over the 135mm, at 5.6 at least.

In your opinion and experience, would I expect to do better with the Canons and or Nikon? Are they 'more modern' designs you mentioned? (aspherical, etc.)

Thoughts/suggestions always appreciated!.
I think the one at f5.6 cleaned up nicely. That appears to be the most common good f stop for adapted lenses on the Q.
One thing that I find is I get better images if I rein in the exposure on the Q a bit, tending to shoot at -.7 pretty much all the time.
The Q tends to overexpose if left on its own so it can exacerbate lens problems by blowing out the highlights in AV.
I use M mode and dial up the shutter speed to get a negative EV value after setting my aperture on the lens.
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