Re: Making a scanner with a DSLR
I was a little curious as to why I needed fewer frames to cover the 6x6cm negative than I had anticipated. (I suspected my computational abilities.) So I photographed a mm ruler with my 55mm Nikkor. While focused at an indicated 1:1 on the lens, it covered a greater area than the size of the sensor. So I reversed the lens with an inexpensive F-mount to 52mm adapter, and the lens was still short. I added a Nikon K4 extension ring, though, at that brought me very close to a true 1:1. Hopefully, I'll have time to try a new scan tonight.
Re: Making a scanner with a DSLR
Quote:
Originally Posted by
Peter J. De Smidt
While focused at an indicated 1:1 on the lens, it covered a greater area than the size of the sensor.
I thought the 55mm Micro-Nikkor required an extension tube or converter to achieve true 1:1, the same as the Canon 50mm f/2.5 Compact Macro.
Speaking of which, I actually forgot that I own that lens. It is extremely sharp with floating elements is well-corrected down to its minimum focus. But I lacked it's dedicated converter to achieve 1:1. KEH to the rescue--these seem to no longer be widely available and Canon may be giving up on this old, but excellent lens. If it works, it will be oh-so-much more convenient than the bellows arrangement.
Rick "whose project continuation today got interrupted by a wallpaper removal task, proving that visible spare time is a dangerous thing to display" Denney
Re: Making a scanner with a DSLR
Quote:
Originally Posted by
rdenney
I thought the 55mm Micro-Nikkor required an extension tube or converter to achieve true 1:1...
That's what I thought too. From this page:
Quote:
This highly rated lens can reach a maximum magnification ratio of 1:2 (0.5X) with its internal helical focus mechanism. With a matching PK-13 Auto Extension Ring, the ratio can reach 1:1 Life Size (1X)- so does when it is used in combination with a 2X teleconverter such as Ai-TC-200 or Ai-S TC-201. If you wish to achieve an even higher magnification, this lens is best to with a Bellow Unit such as Nikon PB-6 Bellow Unit. With such a possible combination, the magnification ratio can even be reaching to an astonishing 1:3.5 !
Re: Making a scanner with a DSLR
There are two scales for the reproduction ratio engraved on the lens barrel, one with the lens alone and another when an extension tube is used. Apparently the model right before mine could reach 1:1 without an extension tube.
My earlier stitch was at 1:2, which only required 9 exposures for coverage and gave close to a 16x20 inch print @300 dpi. That's bigger than I printed medium format in the darkroom.
Re: Making a scanner with a DSLR
My 55 micro Nikkor requires an extension tube. I hadn't owned on prior to this project. I found the PK-13 extension tube for 35.00 shipped which seems to be about the going rate used.
Re: Making a scanner with a DSLR
I expect it'll work best reversed. I bought a cheap f-mount to 52mm adapter new on Ebay for a few dollars. Daniel, do you have the F3.5 or F2.8 version?
Re: Making a scanner with a DSLR
I don't think there's anything magical about 1:1 magnification. I would keep increasing the magnification until the lens can't resolve any more detail or you don't see any more detail in the printed image. I suspect the later will/should be the limiting factor.
Re: Making a scanner with a DSLR
1:1 is a pretty good goal for current lenses and cameras. The top DSLRs can resolve a real 60-70 lp/mm on the sensor with a decent macro lens, which should approximate the level of information in a color negative. In a few years, you'll be able to do better, but there's no reason to shoot for worse.
B&W of course is another issue. To get everything out of a fine B&W negative, you may need greater than 1:1 magnification, or a higher-resolution camera. We're probably a few years away from being able to do that easily.
Re: Making a scanner with a DSLR
Ben, I think we may be on that peak sooner than later. A D800E paired with the 55 Micro Nikkor or the 60mm f/2.8 might be all one would want or need, based on Peter's results so far. Peter, I've got the 2.8 version.
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Re: Making a scanner with a DSLR
Did a little test of my own using my Pentax K-5 and a Pentax 645 120mm macro lens. The setup was rather crude: a dinky Manfrotto travel tripod with ball head sitting on my light table. The negative was taped to a piece of ground glass, and the negative was shifted under the lens using the small ruler to guide the shifting (overlap was done visually through the viewfinder). Magnification was about 1:1.5 and the 4x5 negative was shot in 4 rows of 5 frames. The .DNG files were color neutralized in Camera Raw, TIFFs exported, and the TIFFs stitched using Photoshop's Photomerge. My first couple of tries yielded some out of focus frames which was solved by putting more stable support under the tripod leg sitting on the light table's Plexiglas. The camera was leveled with a 2-way level sitting on the lcd screen, but there was a bit of geometric distortion which resulted in Photomerge making one edge of the negative a bit wonky. Tonally the results were identical, but the sharpness and detail from the DSLR stitch are impressive compared to the Epson V700 (2400 dpi scan). Now I'm curious to try at higher magnification. The Epson crop is unsharpened, but I just realized the Camera Raw frames would have been sharpened at CR's default settings. I didn't find shooting and stitching the 20 frames too onerous considering the results...
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