7 lenses at 1x - Discussion

[PaulFurman]

Edit: this was too much work to assemble in a way that is manageable, I'll leave what I've got but can't figure out a better way to present them all.

Repeated text to make it easier to quote:

Because there are so many images, I made another thread for the images 7 lenses at 1x - Test shots only. They can be opened in separate windows more easily than scrolling way up and down, which drives me nuts, and followup won't require loading everything again. Feel free to post select images in here, just not the whole dang thing.

This is not a flawless test but pretty methodical. I chose a subject with some depth to overcome focus differences and to push the lenses to their limits with flare, CA & bokeh. That's broken pyrex glass on a fern frond with spores developing on black felt. I used a very heavy pro tripod with mirror lockup but it's possible there's some shake still so sharpness might be off but this is more about handling those harsh highlights. I had to do some on a bellows some without so the position & lighting changed a little for some but there's enough similar detail to make the comparisons. Focus was on the fern spore cluster in the center. Unfortunately I didn't get anything consistent in the far corners to test.

4 on 90mm f/3.5 Voigtlander APO Lanthar Close Focus
f/4 on 68mm f/3.5 El-Nikkor
f/4 on 85mm f/2.8 PC Micro Nikkor (.5x without tubes)
f/4 (6.3) on 105mm f/2.8 VR Micro Nikkor
f/4 on 125mm f/2.5 APO Lanthar Macro

First the overview, then three full pixel crops at three different stops. Wide open, f/4 (because they all do that) and f/8. I did more but this was already a whole lot to deal with. Perhaps I'll put up the fully stopped down set later. These overviews link to 1200 pixel reductions.

Now three crops each at f/4 for a level playing field. Again I did my best make them match but it's not perfect. By the end hopefully it'll be possible to make some conclusions or at least know what to test more carefully.

[ChrisR]

What do you make of them, Paul?
One that seems to stand out for not being as good as the rest is the Nik 105 2.8 VR.
So I shall go to bed irritable as I've just paid for one (MF version).

My own experiments give me the impression that many "good" lenses outdo the D700 sensor, at 1:1. In sharpness terms they resolve a black/white step edge to about 3 pixels, which I think as as good as it'll get.
By "good" I mean some better Nikon, Rodagon and Schneider enlarging lenses around 40 - 100mm, and the 55 Micro.
I posted some results here but they weren't well accepted.

[PaulFurman]

The 105 VR is completely different from the manual focus versions :-)

Well it's hard to make conclusions without the layout I intended and now I'm exhausted (what a mess) but, I was mostly looking at flare and CA (chromatic aberration/color fringing) issues because that's what tends to bug me in macro work with all those shiny bits on bugs and flowers. Two of these are APO, corrected for CA, and I consider the 180 nearly APO. I was surprised how well the 105 bellows did! I'll try summarizing my thoughts below.

180mm f/2.8 AF Nikkor
I had heard this is good with extension tubes but it falls apart with a full bellows extension wide open. However it shapes up nicely at f/8. At normal distances it is razor sharp all the way to the corners wide open. CA is great and at normal distances it performs like the APO lenses producing more of a purple fringe type effect (although blue), more like axial CA. This holds true for close focus.

125mm f/2.5 Voigtlander APO Lanthar Macro
My new drool toy that prompted this test. It is possible to produce color fringing in extreme situations like this but it's also noticeably better than the competition. But still, no lens is perfect, there are always trade-offs. The bokeh (can) be oddly harsh in the worst highlights; even but diffraction picks up other patterns causing cross-hatching. Maybe that's natural.

105mm f/2.8 VR Nikkor
CA looks awful though that can be fixed with software, you can't fix it when it shows up in the bokeh. Sharpness compared better than I thought it would. Overall the image looks a lot like the 125 APO.

105mm f/4 bellows Nikkor-P late model
I'm amazed how well this ancient thing performed though there is a certain muddiness, the CA is well controlled, hardly any red fringes, just a more subtle green glow. Bokeh is generally very soft but has bright edges in the worst cases.

90mm f/3.5 Voigtlander APO Lanthar Close Focus
This isn't rated for 1x magnification and earlier tests showed the sharpness doesn't hold up, although it did well in this set. CA shows as purple fringing in extreme situations - more than the 125 APO. Still it renders a very rich clean image.

85mm f/2.8 PC Nikkor
This lens is a favorite of mine and while not rated for 1x, it is rated Micro and holds up nice on a bellows although not as sharp, the CA is low (but not absent) and rendering is consistent to the corners since it's designed for tilt/shift, it should be good at 'only' full frame. However, with really strong highlights like this it can produce strange multiple rings in the bokeh. I've seen that in the 24mm PC-E because it has a lot of elements to get it away from the sensor and still be able to shift. But maybe it has more to do with the large medium format sized elements. I suspect the slow f/4 bellows Nikkor did well because it doesn't need all that glass to do f/2.8 so there is less to go wrong. Anyways the CA and rings caused some serious problems at 1x with these strong highlights which do not ordinarily show.

68mm f/3.5 El-Nikkor
This mystery lens was not blindingly sharp but respectable and almost as good about CA as the APOs. It had a bit of that muddy feel of the old 105 bellows lens but very well behaved in these conditions wide open. At f/8 the bokeh had a coarse bright ring and showed the aperture blade's shape. Opened up there's some 'bat-wing'coma in the corners.

These are all real nice drool-worthy lenses, I should have included some more ordinary ones for comparison. Some of those are tons less sharp at 1x and exhibit all sorts of flaws. This test was designed to make the cream of the crop cry <g>.

[rjlittlefield]

My own experiments give me the impression that many "good" lenses outdo the D700 sensor, at 1:1. In sharpness terms they resolve a black/white step edge to about 3 pixels, which I think as as good as it'll get.
By "good" I mean some better Nikon, Rodagon and Schneider enlarging lenses around 40 - 100mm, and the 55 Micro.

That makes sense to me. Following the guidelines at http://www.cambridgeincolour.com/tutori ... graphy.htm, any lens that is near diffraction-limited at effective f/11 should handily outresolve a D700 sensor.

If you wanted to really nail it down, you might try capturing the lens's projected image aerially using a microscope objective, and compare that to what the D700 captures when the image is projected directly onto its sensor. There is an example of that approach HERE, in THIS thread.

I posted some results here but they weren't well accepted.

I don't remember those. Can you give me a link to them?

--Rik