M645 Macro - 80mm, 120mm, or tubes?

[Kirks518]

I like macro, and I like macro abstract. I really enjoy my M645, and I think it's time I started looking at getting into true macro with my medium formats. I also have an RB67 P-SD, but I think I'd prefer the 645, as I'd be able to adapt it to my Canon DSLR, and sell off my Canon 100mm macro.

So I've been reading and researching, and it seems the 120mm f4 macro is the top lens, but how much better then the 80mm is it? I'm not finding any good comparison info out there. One of the other aspects of the lenses that may be a deciding factor, is how do they each perform at 'normal' focus distances? I've heard that after about 15ft, the 120mm is difficult to focus because it has a very short throw to infinity once you're at ~15ft or so.

Of course the other option is to just use what I have with the extension tubes, but I know myself, and I tend to prefer not to use add-ons. But, if the performance with tubes is good, then I'd probably get accustomed to using them when needed.

And I might as well ask, how does the RB 140mm macro compare?

I'm also curious about macro (1:1) on medium format vs any other format (LF excluded). If I'm shooting let's say a dime (10 cent piece), which is smaller then a frame of 35mm (and APS-C), the image on the 35mm negative will be the same size as the image on the 645 negative. This would then leave a lot of negative (unused) space in the frame. If I enlarge the image for printing, won't the image (of the subject, the dime) be the same no matter which film format is being used, when enlarged the same amount? What then, is the advantage to MF macro over 35mm macro, if any? The only advantage I can think of is getting a 1:1 image of a subject that is larger then a 35mm frame, ie, flowers, big bugs, vehicle emblems, etc. That in and of itself is a bonus, but is that the only advantage?

 

[MattKing]

Lots of questions!

I have the 80mm macro for the Mamiya 645, the 140mm macro for the RB67 and a 50mm macro for my Olympus OM 35mm cameras.

If you are photographing a dime, you will need larger than life magnification on 6x4.5 or 6x7 if you wish to get more benefit from those larger formats. With greater magnification, you will get less depth of field, but with something relatively flat like a dime, that may not matter to you.

if you do fill the larger negatives, you will of course gain the usual benefits that come from a larger negative (or slide).

One important thing to understand about macro lenses is that one of the criteria they should be optimized for is flatness of field at macro distances. In addition, for those abberations and other distortions that tend to vary with shooting distance, the macro lenses will be likely to be optimized to perform better than non-macro lenses at close distances.

The 140mm macro lens for the RB67 illustrates this nicely. Some of the shorter RB67 lenses actually give you greater maximum magnification than the half life size offered by the 140mm lens alone, but the 140mm lens gives better flat field results at half life size and, with extension tubes, larger. Part of that comes from the close focus optimization, and part of it comes from the floating element.

All of my macro lenses perform well for me at non-macro distances. While they are not as fast as their non-macro brethren of similar focal length, in the case of the 50mm Zuiko lens and the 80mm Mamiya I am happy to use them generally when I need those focal lengths. And in the case of the 140mm RB67 lens, I really like that focal length when a short telephoto is useful - I often carry my RB67 with the 140mm and a 65mm lens, which together make for a somewhat compact kit.

One further point, and a reason to consider the 120mm lens for the 645: a longer lens will allow for a longer working distance. That can make lighting your subject quite a bit easier.

 

[benveniste]

I use medium format Pentax gear, so I can't speak to any specifics about the Mamiya line. As MattKing mentioned, flatness of field is one of the key advantages -- I found this was the case when I compared the Pentax 120mm f/4 macro to the 135mm LS and the newest 50mm f/1.8 Nikkor to the older 60mm f/2.8D Micro-Nikkor. Another advantage is that it's not either/or; extension tubes and other accessories work with a Macro lens to allow you to achieve magnifications above 1:1.

If I wanted to "fill a 645 frame" with a U.S. dime, I could do so by using the 120mm macro lens, a set of extension tubes providing 79.8mm of extension, and a Marumi +3 diopter close-up accessory lens. I have not attempted that, but I have used one or the other at various times. For example, I photographed a 27mm diameter gold coin using just the close-up lens and was able to print the shots at 36." The prints now hang right outside the accounting office of a friend's business.

As with smaller formats, the largest challenges with such high magnification of coins is keeping the camera stable and getting even subject lighting despite the small working distances involved. I use a Beseler copystand originally designed for medium format, but of course that adds to the initial expense. I freely admit that I do a lot of my macro "stuff" with smaller formats (including a dSLR), but I really enjoy the challenge offered by medium and large format macro "stuff." So once again this year, I'll be trotting out a 4x5" macro setup once the rhododendrons are blooming locally.

 

[Kirks518]

I guess I should clarify, I don't shoot coins. Ever. I was just using a dime as a size example.

As it is, I order the 120mm from KEH today. Should be here on Wednesday.

 

[benveniste]

Enjoy the lens!

 

[Kirks518]

Thanks benveniste!

So the 120mm got here today, as well as an adapter to use Mamiya 645 lenses on EOS systems. Also picked up an adapter for RZ to EOS, which also happens to work just fine for RB lenses.

So, in all honesty, I cheaped out on the lens, and bought one that was rated as 'Ugly'. I usually never buy Ugly, as by definition, there will be imperfections that will affect image quality. I've bought all sorts of KEH grades, and I know that with Ugly, it is returnable. So I figured worst case, I return it. I was expecting either fungus, scratches, haze, large chunks of debris, or any combination of those. When it got to me, I spent about 15 minutes looking it over, trying ti figure out why it was rated as Ugly. I saw nothing. So when I got home, I did the flashlight test. As best as I can tell, there is very minimal spotting on the interior. Could be the beginnings of 'haze' or it could be just dust, I can't tell. As for everything else, all looks like it would fall into the EX to EX+ grade. No dents, scuffs, scratches, clean blades, etc.

In any case, I'm keeping it.

I slapped the adapter on my Canon 50D, and shot some stuff in the backyard. I'm very impressed with this lens. I have a feeling I'll be selling my Canon 100mm macro in the near future.