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05-01-2014, 04:42 PM   #1
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Slide Duplication: Image is tack sharp in viewfinder but captured image is not.

Using an auto bellows on my KM with a 50mm lens (not reversed) I can see a sharp image in the viewfinder but the image that's captured is fuzzy. Any insight?

05-01-2014, 05:08 PM   #2
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QuoteOriginally posted by MD Optofonik Quote
Using an auto bellows on my KM with a 50mm lens (not reversed) I can see a sharp image in the viewfinder but the image that's captured is fuzzy. Any insight?
What shutter speed were you using? The fuziness could also come from noise or just the narrow DOF. Seeing a sample would certainly help us diagnose the problem.

Normally I'd recommend focusing via live view, but alas the KM doesn't have that

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05-01-2014, 06:46 PM   #3
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You were on a tripod, right? Did you remember to turn off SR?


Steve

---------- Post added 05-01-14 at 06:53 PM ----------

It just occurred to me, that tripod or not, the subject is always constant to the lens when doing slide duplication and SR should always be turned off.

Steve
05-01-2014, 07:50 PM   #4
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QuoteOriginally posted by stevebrot Quote
You were on a tripod, right? Did you remember to turn off SR?


Steve

---------- Post added 05-01-14 at 06:53 PM ----------

It just occurred to me, that tripod or not, the subject is always constant to the lens when doing slide duplication and SR should always be turned off.

Steve
Your shake reduction theory is interesting. I was, however, able to use a high shutter speeds up to 4000 and apertures between f5.6 and f16 because I was pointing at the sun through some clouds. I took off the bellows and double checked the lens on its own with no problems, nice and sharp.

05-01-2014, 08:16 PM   #5
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QuoteOriginally posted by Adam Quote
What shutter speed were you using? The fuziness could also come from noise or just the narrow DOF. Seeing a sample would certainly help us diagnose the problem.

Normally I'd recommend focusing via live view, but alas the KM doesn't have that
Here's a few examples. First, I'm checking the lens only. Second is with the bellows. Third is just now with bellows and SR off (color balance is s*** because... it just is, doesn't matter). I'm baffled.
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05-01-2014, 08:56 PM   #6
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Looks like SR is shaking (feedback loop?)

---------- Post added 05-01-14 at 08:57 PM ----------

Oh--sorry I missed where you said SR off. It does appear to be motion related.

---------- Post added 05-01-14 at 09:00 PM ----------

And it appears the picture is not equally in focus, so likely not parallel to the lens.
05-01-2014, 09:29 PM   #7
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Is the transparency even? Minor bends or curls in film can be very noticeable when following some methods.

M
05-02-2014, 03:45 AM   #8
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So I switched to the K30, used live view and focus peaking indicated the slides are not flat. Nevertheless, even the areas that indicated proper focus were blurred. The image in the viewfinder and on the LCD is sharp. Does the Pentax slide duplicator accept glass slide holders?

I've also ordered a converter for an enlarging lens I have. The SMC Pentax-FA 50mm F1.4 may not be the flattest focus even at the moderate apertures I used.


Last edited by MD Optofonik; 05-02-2014 at 04:35 AM.
05-02-2014, 07:19 AM   #9
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QuoteOriginally posted by MD Optofonik Quote
Does the Pentax slide duplicator accept glass slide holders?
They all should.

http://kmp.bdimitrov.de/misc/macro/index.html

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05-02-2014, 07:59 AM   #10
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QuoteOriginally posted by MD Optofonik Quote
The SMC Pentax-FA 50mm F1.4 may not be the flattest focus even at the moderate apertures I used.
Try a 55/1.8 or any of the 50/1.7's. If you don't have one, PM me and I'll lend you my M50/1.7. They were specifically developed for flat work (shooting flat objects from a copy stand or copipod) and are known to be sharp corner to corner. Mount your bellows on a tripod and use a remote trigger or the 12 second timer - even bellows rails flex a little bit and your slide holder might have a loose mount attachment. If possible, shoot indoors with a studio light shining into the slide. When using film MLU and a cable release was an absolute necessity for duplicating.

An older gentleman who gave me his extensive collection of Spotmatics and Super Takumar lenses (and his entire darkroom setup) told me the 50/1.4's, especially thee pre-A lenses, were optiimized for a portrait style on film that was, at their time, desireable. It was thought a good portrait should be sharp in the center (subject) and just slightly soft at the edges even when shooting a small aperture. On film that created a 'glow' or subtle 3D effect that people liked at the time.

Take all of the above with the usual skepticism since I have only shot once or twice with a copipod - and then only with film (but it is a lot of fun to do). I have a 49mm lens plate and almost all my lenses are 52mm filter threads.

Last edited by monochrome; 05-02-2014 at 08:12 AM.
05-02-2014, 03:34 PM   #11
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QuoteOriginally posted by MD Optofonik Quote
So I switched to the K30, used live view and focus peaking indicated the slides are not flat.
That makes sense; slides are seldom flat. What aperture are you shooting? You may have to go fairly narrow. As you noted, your 50/1.4 may have field curvature that is significant at that magnification and which is contributing the focus problem. As Monochrome suggests, a 50/1.7 or similar might work better.


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05-02-2014, 04:23 PM   #12
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I've digitized lots of transparencies for clients. For smaller 135mm film I've used my Minolta film scanner. For larger archaic oddball sized medium-format slides I've either used a Epson flatbed scanner or a homegrown approach similar to the OP's. Instead of those bellows devices, I simply inverted my old color enlarger head and shot with a DSLR held overhead by a tripod with a horizontal arm. The color head allows for white balance corrections caused by faded dyes. You can also continue working after the sun goes down.

While I made a custom transparency holder for the medium format slides out of thick foam board, for 135mm the enlarger's carriers would work well as it hold the material firmly but is hinged for quick access. My real point here is that I always use a macro lens--either a FA 50mm f2.8 or a Sigma 70mm f2.8.

M
05-11-2014, 09:16 PM   #13
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I got a cheapo "Continental" 50mm enlarger lens and attached it to the Auto Bellows with Slide Copier and this is the image I got. It's a little better, I guess.However, I took delivery of a Primefilm XE and the images are much better albeit with a some color cast issues.


I posted some images using three different software packages here.
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05-12-2014, 12:02 PM   #14
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What aperture setting were you using when your images were blurry?
05-12-2014, 12:13 PM   #15
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On the 50mm FA50 I was between f5.x and f16.

What monochrome stated about the lens being designed for portraiture makes a lot of sense. The Primefilm XE or XA could be the immediate solution for this; something to be revisited at a later date perhaps. I'm happy to have made the attempt since it allowed me to discover what a bellows can do for macro work.

Last edited by MD Optofonik; 05-12-2014 at 12:21 PM.
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