Do macro lenses optimized for f/22 even exist?

[jvanhuys]

Hi there.

This is just for fun OK, but I'm testing a whole bunch of my lenses for close-up shots of food. When I say food, I mean as my wife puts down the plate I have to snap then eat, then take care of baba. I'm using a digital full-frame sensor.

My regular consumer 'macro' lenses all exhibit quite a bit of curvature, which is unattractive.
The other problem is they have severe diffraction at f/22.
At less than f/16 there's just not nearly enough food in focus to make a nice picture:)
Stacking is not an option for me, as I have a time-frame of about 1 second before my wife gets annoyed with the whole setup haha!
I got some very sexy results using a cheap Componon-S 80mm, but still a tad too tight.

Obviously north of 100mm focal the curvature generally is nice and flat, but I find that I just can't frame anything at 100mm. Ideal framing for me so far happened between 60mm and 80mm focal lengths.

So why am I not just sticking to the Componon-S and call it a day? Because it flares like nothing I've ever seen in the real-world. Just curious what else is out there... maybe some lenses start at f/11 and go up to f/64 or something silly. I know some LF lenses are optimizied for f/22 but the COC is just too big for a full frame sensor, so I guess the sharpness will suffer quite a big.

Excited to hear your opinion. Thanks for your time. I appreciate it.

[Lou Jost]

Some lenses do mysteriously do better than others at f/22, but the real problem is physics. Diffraction blurring is more or less proportional to f number. If your results are blurry at f/22, this is almost certainly not due to lack of lens optimization but rather just due to physics.

You might as well just try lens shades and other techniques to reduce the flare on the lens that you like. And if you can't improve the flare, try another similar lens.

Enlarger lenses are probably your best bet for the flattest fields. But I'm puzzled by your comment about most macro lenses having significant curvature of field. That is not my experience. And even if it were, at f/22 with a 3-dimensional subject like a plate of food, the slight deviation from flatness would not be noticeable. And even if it were noticeable, this is easy to fix by stacking.

Lou

[jvanhuys]

Hi Lou. Thanks for your response, I appreciate it. I think the curvature also has a lot to do with focal length and the resulting lens design required.

If you look at any 'consumer'macro lens between 50-75mm you will inevitably see an assymetrical gauss or double gauss design. Even if you look at line scan lenses or enlarger lenses... it's uncanny how the designs suddenly become symmetrical at 80mm or longer.

The weird thing is I saw this in my images years before looking at lens designs. The dead give away was when I photographed a pair of shoes.once, from an isometric viewpoint. I've yet to find a single lens between 25-75mm focals that does not pull the shoes towards the horizon. The moment I switch to let's say a Componon s 80mm or Micro Nikkor 105mm everything just looks the way it should... the shapes appear normal. Of course I have seen 85mm lenses that displayed curvature but I'm pretty sure they were asymmetrical in design.

As I mentioned already i cant stack coz I got like one second to take the picture. But yeah, you're right, some shading or deeper lens hoods seem to be the only way to use enlarger lenses in this real-world context.

I bought a cheap el Nikkor 63 today just coz the design seemed more symmetrical than say an Apo componon 60mm to me ( and way cheaper of course), but I'll post here if I'm happy with it.

Hope you have a good evening and chat soon.

[Lou Jost]

From your description of the shoes, I think what you are calling "curvature of field" may be something different from what I was referring to.

Try taking a picture of something perfectly flat, exactly perpendicular to the lens axis. If it is all in focus at the same time, then the field is flat.

Even short macro lenses pass this test. They have to, because one of the main uses of macro lenses is copy work.

Maybe you are actually talking about perspective instead of field flatness?

[AlP]

I would use a tilt/shift lens. Canon's last batch of T/S's offer 1:2 (0.5x) magnification.

[jvanhuys]

@Lou. I think you got me there. Cheers for the correction.

@AIP. That's a great idea thank you! I'll definitely look into that.

[Lou Jost]

That's a good suggestion for reducing perspective problems. Their field flatness is surely worse than that of dedicated macro lenses though. So the original poster needs to specify whether the problem is really field flatness or perspective problems. I suspect the latter, and in that case using a tilt/shift lens and view camera techniques would be a great solution.

Edit: I see this has been clarified just now, while I was writing. Great!

[Pau]

Admin edit:
Thread moved to Macro and Micro Technique and Technical Discussions forum where it's better placed

[enricosavazzi]

Some lenses do mysteriously do better than others at f/22 [...]

I think the most likely explanation is that they have a high pupil ratio, which results in a lower effective aperture at a given magnification, compared with an ideal thin lens (which has a pupil ratio of 1). So this is also physics.

Ae = An ((R / P) + 1)

Ae: effective aperture
An: nominal aperture
R: reproduction ratio (same as magnification)
P: pupil ratio defined as Pout / Pin

Of course with a lower Ae comes also a lower diffraction and DoF. There is no way around it.

[Lou Jost]

Yes, it is just mysterious because the pupil magnification ratio is usually not stated in published lens tests.

[jvanhuys]

Fascinating concept this pupil ratio. I must confess I've never heard of it before.

Just wondering why manufacturers don't elaborate on this more.... hmmm.

Thanks for sharing the concept.

[enricosavazzi]

Fascinating concept this pupil ratio. I must confess I've never heard of it before.

Just wondering why manufacturers don't elaborate on this more.... hmmm.

Thanks for sharing the concept.

There is some more information at http://www.photomacrography.net/forum/v ... =29&t=8895