Macro photography with and without macro lenses

[cjj2003]

Hello!

I'm attempting to do macro photography with a Sinar P, 210mm MC Sinaron-S lens and Leaf Aptus 22 back. I'm comparing the results to my Canon 5dMk2 and 180L macro lens. To my eye, the results are indistinguishable @ f/22 (no movements) in terms of sharpness, contrast, etc. Would a true macro lens improve the image from the Sinar/Leaf? I'm looking at a Rodenstock APO-macro or Nikkor Am at 210mm.

Keep in mind that the Canon and Leaf back have the same resolution but the Leaf has no AA filter, so I was expecting it to produce sharper results, at least at the pixel level.

Thanks in advance for your advice,
Chad

[Dan Fromm]

How close is macro, i.e., what magnification are you working at? The Leaf's sensor is larger, 48x36 mm, the Canon's is smaller, 24x36, i.e., half frame. Tell us more about the shots you're comparing and how you're measuring "sharpness."

[cjj2003]

Good point. At the moment I'm comparing images of a watch dial and judging sharpness by eye at 100-300% magnification in photoshop. The Canon is at slightly more than 1:1 magnification (with a short extension tube) and the Leaf is at slightly less than 1:1 magnification -- in such a way that the field of view is approximately the same (ie. the face of the watch roughly fills the frame on both so when I view them side by side at the same magnification in photoshop they are the same size).

[Bob Salomon]

To really see the difference you would use the macro digital lens not the analog one. For digital it is the 120 Apo Macro Sironar Digital. For film it would be the 120mm Apo Macro Sironar.

You would also see better digital results with a digital view camera like the M679cs or the Techno where the gearing is much more precise then the controls on an analog view camera.

[Dan Fromm]

Other things equal, if you shoot the Canon at higher magnification it will do a better job of separating fine details in the subject than the Leaf back will. Other things equal.

A watch dial isn't the best subject. You want a subject with fine details at a range of spacings so that you can estimate how well the lens/film (I know you're shooting digital) combination you're using separates fine details. Resolution is about separating fine detail. You also need fine detail all over the subject to see how well the lens/film combination does towards the edges of the field.

The Canon lens is probably best at around f/8 - f/11, that's how my manual focus MicroNikkors are. The Sinaron is probably best around f/22. And, as Bob suggested, a real macro lens for medium format has got to do better close up than the Sinaron, which is optimized for something like "far away."

[cjj2003]

Frankly, I don't understand how anyone can do macro photography with a 120mm lens. That means I have to be 12cm from my subject. Where do I put my lights!? But that's another topic...

I suppose my real question is, what is the real world difference between a regular lens and a dedicated macro lens? Ideally I'd love to see some side-by-side comparisons.

[cjj2003]

Yes, I thought f/22 would give a clear advantage to the leaf over the Canon, that's why I was surprised by the results. I agree I need a better test target.

[Patrick13]

Not sure where f22 falls in in that area where your chosen lens' diffraction overtakes the quality from stopping down a bit? You may be hiding the difference in fuzz. My 105mm macro seems optimal around 5.6 to 8, for example.

Also, you should add a flat subject like a stamp to your tests in addition to subjections with dimension to check against field curvature where a macro lens should be more flat up close.

PS: for macro, a ring light means never having to say I'm sorry.

[Bob Salomon]

Yes, I thought f/22 would give a clear advantage to the leaf over the Canon, that's why I was surprised by the results. I agree I need a better test target.

The Canon has an image size of 24 x 36mm while the Leaf is a 645. To get the depth of field on a 35mm equal to the Leaf, with the same focal length lens you have to be stopped down further on the Canon. But at f22 on the Canon you will be in diffraction.

With a modern digital macro lens for the Leaf on your Sinar optimal aperture will be at f8 to 11. On your Sinar 45 with film optimal aperture will be at f22. On your Canon optimal aperture will be about 2 stops from wide open.

Then compare results.

[Dan Fromm]

Frankly, I don't understand how anyone can do macro photography with a 120mm lens. That means I have to be 12cm from my subject. Where do I put my lights!? But that's another topic...

I suppose my real question is, what is the real world difference between a regular lens and a dedicated macro lens? Ideally I'd love to see some side-by-side comparisons.

Not quite right. Lens' front node (usually located near the diaphragm) to subject distance = lens' focal length requires infinite magnification. In the range of magnifications you've told us about, front node to subject distance is around twice focal length.

Re diffraction and all that, you may be in trouble at marked f/22, effective (near 1:1) f/44. You'll certainly be in trouble at marked f/32, effective f/64.