Coin Photo Setup

Thanks Ray for putting all that together for me. I really appreciate your time. I've read over your last couple of posts numerous times and my biggest problem is the terminology. A lot of it to me as a novice is more Greek than English. But I'm "werkin" on it with Wikipedia's help.

As I understand it so far, I need the Canon to M42 mount (adapter) as shown here http://cgi.ebay.com/M42-Lens-Canon-...em19c3ef86f6 ? I have a Canon EOS REBEL XT.

Next you mention 3 ring M42 extensions. These can be bypassed if I should opt for the bellows only? You mentioned the Asahi Pentax single-rail bellows http://cgi.ebay.com/ASAHI-PENTAX-BE...em1e63a42f93 Would this set-up (minus the extension rings) return my aperture controls? For versatility I'm thinking the bellows set up would offer quite a bit more focus control than the extensions?

The Nikon 75mm f/4 enlarging lens sounds good to me since you believe it's the better lens and it still has a very reasonable price.

All sounds good! That type of adapter is what I was thinking of in last post. And you are correct, the bellows will replace the extensions and give you much more focusing versatility. You will still need an adapter for M39-M42. I was thinking of these:

http://cgi.ebay.com/Leica-M39-Lens-...em41577b9b59

Here's an example of the Nikon lens, already sold, but this is what I am talking about:

http://cgi.ebay.com/Nikon-El-Nikkor...em3f09a7d77d

Thanks guys for all the info. From what I have been able to gather, that Nikon El Nikkor has a manual aperture ring so that might take care of the loss of control?

SD, hope it all works out after I finish putting together this camera "erector set". Just kidding.

No I certainly can't complain about the price. I was concerned about getting the f/stops back though as Ray had mentioned he thought part of the reason I was losing definition on the peripheries was my aperture which read f/0 in the meta but I'm sure that's because there was no electrical connection to the camera. No idea what it was in actuality. The other part being the lens not being designed for "flat field work". No idea what that means but I seem to need it. I noticed you said you'd be working at f/8 with your canon and that Takumar.
http://cgi.ebay.com/ws/eBayISAPI.dl...d9PYZ8A%253D Looks like a real honey and great price. I'm putting it down as my next project but first I'm really interested in seeing what I can do with the bellows angle.

Most "taking" lenses, ie those designed to be mounted to a camera for taking pictures, are not flat-field optimized. Not many subjects of real-world photographers are flat, so other aspects of lens performance are usually emphasized. But for taking pictures of coins, flat field optimization is very useful since coins are relatively flat.

Conversely, most "enlarging" lenses, ie those designed to be mounted to a contraption to project the image from the FLAT film negative (small) onto FLAT photographic film (large), are optimized for flatness of field. They make very good lenses for taking coin photos.

As it turns out, making a stack of lens elements all do the right thing over their entire surface, especially the outer edges, is very difficult. Even if there is no distortion, getting all the wavelengths of light to converge in proper focus is very difficult to achieve over the entire lens surface. Most all lenses thus benefit by restricting the image to travel only through the central lens areas where the light path is easier to control. This is "stopping" down the lens, which is really just making the lens an effectively smaller diameter, and has the effect of optimizing the flow of light through the lens and making it so the different paths come together in better focus. Fewer paths for the light to hit the film/sensor means less possibility of lens aberrations and non-idealities compromising the focus/color/etc of the image.

Sidekick-CA, from your pictures it looks like your lens aperture was wide open. Thus the light was going through essentially the entire lens surface and there was a lot of opportunity for some of the light to travel unwanted/unfocused paths and cause problems at the sensor. Lots of light got to the sensor, but some of it was mis-aligned from the rest and this resulted in a blurry image, especially around the peripheries.

It is actually very common for taking lenses to have this behavior. Some are even optimized to be fuzzy at the edges on purpose! Many of the famous "portrait" lenses are like this. The Nikon 105/2.5, a lens famed for portrait use that has been used for many famous shots, is quite fuzzy on the edges wide open, but quite clear in the center. This is great for portraits, which need to emphasize the person's face in the center of the image and often are blurry around the edges.

SuperDave...Actually, I haven't been doing photography for very long. I bought my first DSLR in Oct '09 (a D5000) and since then have been researching and experimenting to get the best coin photos I can. I'm not an old film guy turned digital, just an enthusiastic engineer with a coin collecting hobby who wants to document his collection best he can for archiving and selling. From my username you might be able to guess that I am an RPM collector, and in fact my passion is Lincoln Wheat RPMs and Doubled Dies. Before I started down the path of "whole coin" photos, I was taking microscope-based photos of varieties for attribution. Recently I have integrated the DSLR to the microscope, and have been getting fairly good results.

As an example, I just last night found a new DDO in a BU roll of 1942-D Lincolns. At least I think it's new...I just posted pics last night on Coneca's Die Variety Forum and they're being reviewed. Here is the link:

http://board.conecaonline.org/showt...71#post11371

I'll post the main pic here for reference. This was taken with my D7000 mounted on a Bausch & Lomb MonoZoom7 with a ring light for illumination. Stand is similar to the one used on the Coin Macro Setups, but with adapter for the MonoZoom7. The microscope has a 1x objective and a 1.5x ocular adapter. I have a 2x objective and 3x ocular adapter available, so could get 4x the magnification vs what is shown here, but this seemed enough to document the doubling on the coin.

Note this setup isn't all that expensive. I think I paid around $300 on ebay for the microscope, though a ready-made setup may cost you much more. Basically, I'm patient and pick things up when they present themselves at a good price! Later I'll take a pic of the setup so all can see what I'm talking about. I may also put on the 2x objective and see if I can get a bit higher resolution...Ray

It's most definitely worth it. I can get much more for a coin with a good picture than without. Return on investment is pretty quick.
No pics = no sale
Bad pics = low sales price
Good pics = competitive bidding
Excellent pics = top dollar