Bought An Apo-Rodagon D F4 75mm 1:1 Macro Lens

Firstly, you got an absolutely STEAL on that lens for $99! I paid $230 and $270 for my two examples.

Regarding the sweet spot: you will want to keep it between f/4 and f/8 on the turn dial. Mine never goes above the half-tick between 5.6 and 8. I have shot wide open (f/4) only when I'm doing a 3-stack or something like that. 5.6 is a pretty safe bet if you want to "set it and forget it".

To attach your 75ARD1 Lens to your bellows you need an adaptor like this one: http://www.ebay.com/itm/Leica-M39-L...320968767651

You used to be able to find these for like $3 each from US sellers, but the ones I purchased about a year ago (from the exact same seller) are now listed on ebay for $23 each! Insane. It's worth ordering now as they will come from China and will take a while to arrive.

OK: sorry for the multiple posts, but here is a cheaper example from a USA seller ($1.95 + $3 shipping from Illinois)

http://www.ebay.com/itm/Leica-Leitz...390087432440

Regular orientation, yes.

You purchased the correct version, the one optimized for 1:1 magnification. The other one is optimized for 2:1 magnification.

I purchased both of my lenses on the Bay between 1.5 and 2 years ago. They don't show up on ebay all that often for less than $300 in excellent or better condition. The one I got for $270 was absolutely mint/gem condition. I'm not convinced it was every used at all. I think you will really like this lens. I can't find any complaints really for the money. I think Ray has converted many numismatic photographers to this lens. I know of 4 that do very good work with this particular lens.

I forget, are you shooting Canon or Nikon?

WOW West, great deal on the 75ARD1! I've purchased the fixed aperture version for around that money but never a variable aperture one.

As for best aperture, it mainly depends on the size of the coin you're shooting. Looking at your camera list, all are FF except the 7D, so it might seem they would require different apertures. However, the higher magnification required by the FF cameras is offset by the higher pixel density of the 7D, so ultimately the optimum aperture is not so different. All your FF cameras have DLA of f10 or so, while your 7D is around f7. But your FF cameras need a higher magnification to fill the frame. As an example, let's say you're shooting Cents, which are 19mm diameter...

mag for FF is 24/19=1.26
mag for 7D is 15/19=0.78

To keep the system right on the edge of being diffraction-limited, you need to keep the effective aperture at or below the DLA of the camera. The equation is:

min lens aperture = DLA /(1+m)

for the FF cameras, MLA = 10/2.26=f4.2
for the 7D, MLA = 7/1.78=f3.9

So to stay inside the DLA of the camera, you need to run your lens wide open at f4. The FF cameras will have less DOF because they are being run at higher magnification, so there may be a slight advantage to the 7D. Bottom line, it doesn't really matter which camera you use, the results should be fairly similar in image quality for Cents.

Now, running wide open at f4 may not give good enough DOF even for the 7D, so you may want to drop down to f4.7 or even f5.6 for Cents. I shoot Cents at f4.7 as a compromise between lens aberrations, depth of field, and diffraction on my T2i, which has the same sensor as your 7D.

The 75ARD1 is a duplication lens, and is most at home around 1:1 magnification. For Dollars, the magnification on FF is 0.63:1, and on the 7D it's 0.39:1. This gives the advantage to the FF cameras as they are being used nearer to the optimum range of the lens. The result is that you will want to stop down the lens a bit more on the 7D than on the FF cameras when shooting Dollars. On my T2i, I shoot Dollars at f8. This gets the lens well into the range where it is sharp across the field. For the FF cameras, you might get by with as big as f5.6 but I'd suggest f7.1 to be safe. Ultimately the effective aperture is still about the same, since f8 on the 7D will be f11 effective, while f7.1 on the FF cameras will be f11.6 effective.

As you can see, it probably doesn't matter which camera you use, but your aperture settings need to be tailored to both the camera and the size of coin you are shooting.

If you're not tired of playing around, you can always set the aperture wide open and experiment with z-stacking.

If I recall correctly, brg is (like most of us image geeks) on a Canon dSLR/bellows setup. The Canons are favored because of their electronic first shutter screen, which rmpsrpms has demonstrated to be superior to Nikon's implementation in terms of lesser induced vibration affecting final sharpness.

So keep in mind, if you buy a used Canon 450D or newer, a cheap bellows setup on ebay, and any one of a number of cheap duplicating lenses, you can shoot images that are 95% of the very best ever seen here, for the price of a nice P&S.

Now this will get some people thinking...if your that worried about Mirror vibration then have a look at one of the new sony DSLR like cameras.........though they look like a DSLR they aren't: the translucent mirror doesn't move at all.