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05-10-2017, 03:50 AM - 3 Likes   #1
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DSLR scanning - an unexpected benefit of the K-1!

So my workflow has hitherto involved mounting the Asahi Pentax slide copier on the end of my DA35/2.8 Macro, mounted to my K-5, and discharging a flash into it for illumination. The 35/2.8 is great for this because it has the requisite minimum focus distance to handle this arrangement without bellows; however, I have needed to put a couple of filters on as extenders because the FOV isn't quite wide enough with the slide copier mounted directly to the lens.

Lo and behold, my K-1 and my DA35/2.8 Limited Macro met for the first time last night, and I discovered to my delight that the FOV is more than enough to encompass the complete negative's image while at the same time avoiding (just) the vignetting the lens has on full frame. Yes, I have to crop the extra space around the image out; but given that I'd be taking the raws into post anyway for all but the crudest quick-look scans, it means I don't have to fiddle around with spacers anymore.

Now to see what the 50mm SMC Macro Tak does. I fear I'll probably need extension tubes for this; the MFD isn't even close when compared to the 35.

I may yet end up scanning the whole roll quick and dirty on downsampled, in-camera processed JPEG (monochrome and inverting filters inside the K-1's presets), then using those as a contact sheet to go back and re-scan the best ones as K-1 raw files.

The only downside of all this is now that I know what a good 35mm AF lens looks like at full frame on the K-1, I'm starting to think about an FA35/f2 Oh LBA, go away for a while...

05-10-2017, 04:34 AM - 2 Likes   #2
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QuoteOriginally posted by pathdoc Quote
The only downside of all this is now that I know what a good 35mm AF lens looks like at full frame on the K-1, I'm starting to think about an FA35/f2..
Or perhaps the FA31..

05-10-2017, 06:46 AM - 1 Like   #3
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Lol this forum is full of evil temptresses.. yes no tempters.. temptresses. Lenses are shes and all those who push them on others are temptresses.

I love the 35 ltd. I wish so much that itd work on FF. I haven't been able to part with it. Mind sharing an image of your setup? I've used the 35 for scanning film once and just had the negative taped to a window. I have a box of slides I need to get to work on and need some inexpensive ideas.
05-10-2017, 07:14 AM   #4
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With the K-1, any macro lens setup that can do 1:1 can be used for 35mm film scanning. With APS-C, the macro setup only needs to do 1:1.5.

There's also the potential to use PixelShift will film scanning if you want to capture every single grain in the film (but that requires a stable, non-flicking light source and very stable scanning rig).

05-10-2017, 09:18 AM   #5
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QuoteOriginally posted by pathdoc Quote
I'm starting to think about an FA35/f2 Oh LBA, go away for a while...
The DA35/f2.4 (they call it the plastic fantastic) isn't bad at all for the price tag albeit not a macro. Currently shows $139 at B&H
05-10-2017, 09:27 AM   #6
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QuoteOriginally posted by shardulm Quote
The DA35/f2.4 (they call it the plastic fantastic) isn't bad at all for the price tag albeit not a macro.
Not technically a full-frame either, and with very little to separate it otherwise from the DA35/2.8 Limited. The 35/2 at least has guaranteed full frame coverage, plus it has an aperture ring and could at a pinch be thrown on any of my K-mount film cameras.

As for the 31/1.8... maybe. Maybe one day. Say, next Christmas... (I turned an opportunity down last year at what I realise now was a stupidly low price. Damn fool me, but then I never dreamed at the time that I would be owning a K-1 so soon.)
05-10-2017, 01:41 PM   #7
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Why would not having a K-1 yet have anything to do with wanting an FA31? I want one for my K-3! 😀
05-10-2017, 02:03 PM - 1 Like   #8
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QuoteOriginally posted by TheOneAndOnlyJH Quote
Why would not having a K-1 yet have anything to do with wanting an FA31? I want one for my K-3! 😀
Because I already have an FA28/2.8 and FA28-90/3.5-5.6 and the 35 macro plus a Super Takumar 35/3.5, so that focal length range is well and truly covered. As a hobbyist-enthusiast I have to pick my battles carefully; I elected to upgrade the body this year rather than buy glass the way I did in late 2015 (I could have had the K-1 for Christmas but deferred the purchase as between business trip, family holiday, foul weather and busy work, it would have been wasted).

05-10-2017, 03:30 PM   #9
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I believe you, I only meant that jokingly. I completely understand how it is spending hard earned money on a hobby, and some things will always be hard to justify. Unfortunately the FA31 and K-1 will probably only ever be a dream for me, but I can still drool!

05-20-2017, 06:05 PM   #10
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Thoughts on further experimentation tonight...

First of all the rig - K-1, DA35 Macro, and the usual 49mm UV filter on the front (because most of my work shooting is in a wet environment with toxic chemicals that I want to keep off the front element), which offers my Asahi Pentax slide copier something to grip on. With the copier mounted directly on, the lens sees the frame of the copier and the entire slide within it. The vignetting, if any, at this distance is clear of the actual image I want to capture (bonus!). The illumination is from a bright 50W-equivalent LED downlight in the ceiling.

In-camera settings (fixed throughout) - ISO 1600-3200 to keep the shutter speed up for these impromptu tests, monochrome filter, colour inversion filter, f/8.0 for reasonable DOF on the film plane, Av mode, downsampling set to 2.0MP because I'm really only fooling around with exposure and don't care much for detail at the moment. From time to time I went to crop mode to play around with framing, but crop mode costs me the top 5% of my picture and still needs the bottom 5% of dead space cropped away; full frame leaves a bright frame around the actual film image. If I'm going to straighten and crop, I'd rather do it with one setting in post.

The variables - third dial assigned to EV compensation.

The images - randomly selected from the past year or so of B&W film processing (yes, I've been doing it for that long!).

What I discovered: Regardless of what film or camera I had used or what development, +2.0EV got me a pretty good insta-result MOST times, regardless of which strip I pulled out of the negative folder. These are the sorts of results I could put straight on social media with a bit of frame-cropping and straightening and they would be just fine.

Sometimes +2.0 wasn't quite right, and I had to go either higher or lower to get an optimum result. But this is really no different from making a contact sheet and playing around with the exposures on that.

With the scans from these, even without frame cropping, I can have a quick look at all the pictures as positives (black and white photograph equivalents) as soon as the film is dry enough for scanning, cluck over the best ones, and from there rig everything up very, very carefully to take full-scale RAW shots from the negative of the ones I might want to make physical prints from or give to people as high-resolution JPEGs. Then I can take those as negatives into Raw Therapee with the exposure compensation factor already applied and do the monochrome conversion and negative inversion under the control of a significantly more powerful processor than the one in my camera.

That's the idea anyway.

The key lies in thinking like a film photographer rather than a digital one. In this case my sensor and processing system are the "paper" via which the negative image is inverted back to a positive. Of course if I'm taking an image for keeps then the whole business will be on a tripod and the lamp will be parked in front of it, and I'll be using live view and a cable release at the lowest ISO possible, but the principle seems well and truly sorted out now. Raw Therapee is by no means the ideal JPEG manipulation tool, but if all I am asking it to do is the same cropping and rotation (something it's pretty good at), there shouldn't be much harm in that, especially since the "raw file" in question is an actual, physical FILM NEGATIVE.
07-04-2017, 05:40 PM - 1 Like   #11
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Further update on K-1 slide scanning technique - the next refinement (it may be the last) was to mount the camera, lens and assembled slide copier on a tripod with a bright daylight-balanced table lamp pointing at it for illumination. Av mode, f/8 selected, and cable release plugged in. Inverting and B&W filters switched on in-camera. XS JPEG size selected. Exposure is of the order of 1/10 at ISO 100. The menu dial is set for EV compensation. Live view activated.

I found to my delight that by twisting the Third Knob, I was given a WYSIWYG view of what each frame would look like as I pulled it through and could adjust for individual negative density on the fly, simply by turning the knob this way and that until it looked about right. Then just trip the cable release and who cares about selected shutter speed or camera shake, eh? This is something I could not have done as easily on the K-5 - it would have required me also to hold down the EV compensation button. Nor can I do it when using flash - with that, I have to take the shot and await results, then repeat as required. So full marks to the K-1 for providing a much improved workflow for digitisation of B&W negatives.

Some of them I did later tweak for brightness and contrast a tiny bit, but the above method leaves very little to do in post except to trim away the excess and occasionally apply a few degrees of rotation, and even Snapseed on my tablet will handle that (in fact it will handle it with far less effort than would a more sophisticated program on a more sophisticated platform). I need to get some 49mm spacers so I can JUST fill the entire frame with crop mode selected, which would reduce the amount of post-processing crop work I have to do even further, but my digitisation workflow just got a whole lot simpler.

(Naturally this method will not rescue a ruined - grossly under- or over-exposed - shot, but for the vast majority of exposures on this roll, it made getting each one onto the card as optimally as possible a breeze. Most of them wanted about +1EV, but not all of them, and this made sure there were essentially no retakes necessary.)
07-04-2017, 06:23 PM - 1 Like   #12
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Since you're shooting B&W, your exposure light coloration won't make a difference. You might gain a fraction on sharpness by using a single color light source (e.g. green or blue), which would eliminate any chromatic aberrations in the lens you use. You can use most any light source and employ a dichroic filter (some low cost 2x2 inch sizes are available) ahead of the diffusing medium. Just make sure the light goes through in a parallel manner (light at angles will change color). Even a single color compact fluorescent lamp would probably have a narrow enough spectrum to work in place of a filter.

Alternately, shoot in pixel shift mode and use only one of the three captured images - the downside is it would take a little experimentation to get the focus right, whereas with the filter method, you can see the correct focus in live view with magnification.

T74 2 Inch Dichroic Glass Filter by Juno Lighting | DGF200DRED

Dichroic Mirror: Lab Equipment | eBay[COLOR="Silver"]

---------- Post added 07-04-2017 at 07:24 PM ----------

Last edited by Bob 256; 07-04-2017 at 06:30 PM.
07-05-2017, 04:03 AM   #13
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QuoteOriginally posted by Bob 256 Quote
Since you're shooting B&W, your exposure light coloration won't make a difference.
Probably not, but I felt it was only proper to document what I was using.

Right now my setup is, I think, optimal - quick to set up, easy to use, and quick to pack away. Any edge I get in sharpness is probably going to be as much improved by working on my focusing technique (all my film cameras are manual focus, and many don't have a split prism) as any sharpening I can get done at the pre-sensor stage. And I'm not above turning up the clarity/sharpness in camera if I have to.
07-05-2017, 07:34 AM   #14
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QuoteOriginally posted by pathdoc Quote
Probably not, but I felt it was only proper to document what I was using.............
Don't take my comment as any criticism. I was just making a suggestion based on your working with B&W subject matter and the fact that many lenses have some color fringing which can smear edges slightly when captured images are converted to B&W (with the K-1). Using a color filter (even a simple one in front of the lens) will get rid of that fringing and add to sharpness, though slightly. In your case, it may not be worth the effort given the small amount of improvement it adds, but just thought it worth to throw in, in case you'd be interested.

Chip makers make use of this principle, and it's the only way they can reproduce chip details at the small scale they use in their photo-lithography. They use lenses that have NO achromatic compensation, and monochromatic light and get resolutions that photographers can only envy (but then again, their optics cost $M). Of course, for color scanning, forget it.
07-05-2017, 08:06 AM   #15
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QuoteOriginally posted by Bob 256 Quote
Don't take my comment as any criticism. I was just making a suggestion based on your working with B&W subject matter and the fact that many lenses have some color fringing which can smear edges slightly when captured images are converted to B&W (with the K-1). Using a color filter (even a simple one in front of the lens) will get rid of that fringing and add to sharpness, though slightly. In your case, it may not be worth the effort given the small amount of improvement it adds, but just thought it worth to throw in, in case you'd be interested.
By all means. I'm tempted to give it a try. A grab-bag of stuff I bought last year included a whole bunch of orange filters someone had bought long ago for playing with tungsten film and lighting, and I can see if any of those are 49mm. I can stick one of those in the optic path and see what difference it makes; I need a spacer or two to bring the film plane a little further out from the lens in crop mode anyway (to take in the entire frame), and though I'm reluctant to put any more glass into the pathway than I have to, the gains might outweigh the deficits in this case. I will report back in due course.
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