Reid Review: 28 2.0 Ultron focus shift

This is an old discussion but let me add my two yen. I have used the Ultron 28/2, Nokton 35/1.4 and Nokton 50/1.1 and have yet to detect focus shift, which I am sensitive to (the old Sonar 50/1.5 for instance). Doing informal tests I find found that the Ultron 28/2 significantly out-performs the Ultron 28/1.9 on the M8, though the latter has aspherical elements. The Summicron 28/2, which I had a chance to test, is spectacular on the M8. I won't pay $4000 for it. But for a good used one..... Stay tuned.
 
I have tried to find the focus shift and have not found it on M8 or film M cameras. On the whole focusing it is considerably less problematic wide open the the Ultron 28mm f1.9, which is supposed to have litte or not focus shift according to Mr Reid. I have found it considerably better wide open than the Ultron 28mm f1.9, sor all its asperical elements. It also handles shadows and highlights better, nearly on par with the Summicron 28mm f2 that I tested. The only thing I dislike about the Ultron 28mm f2 is the parsimoneous d.o.f scale, which is beautiful on the older Ultron.
 
There IS focus shift with this lens, but it's not at all a problem. When shooting close up, it actually focuses a tiny bit too close at f/2. But due to its special drawing (with alot of spherical aberration), things appear to be "enough" in focus anyway. Stopping down reduces SA and shifts focus slightly further away.
At larger distances you get some sort of "extended" DOF due to the SA, with a bit of a dreamy look with smooth transitions into the background blur.

I'd say that the lens is "forgiving". You can misfocus it quite a bit without the pictures looking unsharp. And I really like the special character of it.
 
ampguy said:
maybe the DOF scale should have been this:

<-- dreamy ... dreamier -->

😉
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😀 Really, this lens is tack sharp wide open at short to medium distances, at least on my M8.

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The bokeh is awesome!

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And the distortion is...none!

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Gotta agree with Makten, this lens is an absolute dream to use on the M8. I haven't done any real tests on sharpness, but judging from the pictures i've shot with it at impossible shutter speeds...it's sharp 😀

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Last one is 1/8th at f/2, sharp yes? 😀
 
ampguy said:
wow, nice images, how is the flare shooting into the sun?
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No idea. I haven't seen the sun since I bought the lens.:bang: 😀
But, when shooting street lights and such, I've seen no flares at all!

Stopped down, it's one of the sharpest lenses I've ever tried (and I've tried alot of lenses, on Nikon D700). Here at f/4:

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100% crop:

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Some more nice bokeh at f/2:

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Edit: ashrafazlan, very nice shots!!!
 
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Heck, a couple more... All at f/2, and I think you can see the "forgivingness" of the lens here. At large distances, DOF extends more than you'd expect. The results are smooth, nice and quite sharp.

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Focus shift does happen-- I have my grandpa's old contax IIA with a 50 1.5 sonnar and it's really dramatic-- between f/2 and f/4 it's almost impossible to focus, at any distance (luckily sonnars are great wide open)

I haven't used the 28 ultron, but the 40/1.4 is supposed to be pretty bad too, If I go out of my way to find it by shooting a self portrait in a mirror at minimum focus I will have the point of sharp focus just in front of my eye rather than on it, however in real life photography I've never seen it.

Also note for all of us pixel/grain peepers-- to find focus shift you need to stop down 1-2 stops, shooting wide open prevents the issue. (Apparently ziess has at some time for some weird reason made sonnars that are calibrated for accurate focus at f2.8 rather than wide open which may contribute to the confusion)
 
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fdigital said:
Focus shift is one of the biggest internet myth things I've ever seen.
<snip>
My point is don't waste your time worrying about "focus shift", as it never rears it's head in reality - only maybe during tests with rulers or newspapers or whatever.
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Erm, wrong sorry. Go buy a Nokton 1.1, shoot a close up at about f4. You'll have sharper ears than eyes. I gather the 50 Sonnar has similar quirks.

Focus shift does not appear for SOME people because they shoot outside the affected parameters. This does not make it an 'internet myth'.
 
Lord Fluff said:
Erm, wrong sorry. Go buy a Nokton 1.1, shoot a close up at about f4. You'll have sharper ears than eyes. I gather the 50 Sonnar has similar quirks.

Focus shift does not appear for SOME people because they shoot outside the affected parameters. This does not make it an 'internet myth'.
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Why don't people just focus at the aperture they're shooting at? Doesn't this avoid focus shift? I don't see what all the fuss is about.
 
leicashot said:
Why don't people just focus at the aperture they're shooting at? Doesn't this avoid focus shift? I don't see what all the fuss is about.
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That would definitely avoid focus shift, and is possible only with through-the-lens focusing such as an SLR stopped down to the taking aperture, or a digital with live view using the screen for focusing at the taking aperture.

With an RF camera, it's different, as we rely on the calibration between the lens and rangefinder... The question becomes: Which aperture is the lens set to focus correctly with the rangefinder? At that aperture you get correct focus. If there's focus shift, then at other apertures you have a focusing error.

That may (but not in all cases) be "absorbed" by depth-of-field, and thus not a problem in use. If faced with some focus shift effects, one can also learn that behavior and manually make corrective adjustments after focusing and before tripping the shutter.
 
leicashot said:
Why don't people just focus at the aperture they're shooting at? Doesn't this avoid focus shift? I don't see what all the fuss is about.
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I think you might need to read up a little on rangefinder focussing. Aperture setting does not influence the focussing process in RF cameras.
 
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