edwardkaraa wrote:
Indeed, the ZM 35/2 has practically zero distortion and the ZM 25/2.8 has almost none.
Until you get south of 25, the need for the mustache doesn't seem that warranted in SLR glass. To me 35mm is not that much wider than normal. Until you get to the 21 (where the King rules @ SLR) and wider, it is much easier to keep the compromises at bay. Do the UWA's (south of 25) use it (mustache) in the M mounts?
michaelwatkins wrote:
.... Sony in their grand plan clearly would need a trusted name to get the word out on the A7......
Do they actually have a plan for their photographic product line? To me, I see Sony as only interested in capturing the interest of early innovators and us geeks in the consumer and professional market who are willing to pay a premium as early adopters. Sony have been doing it for more than 30-40 years at least.. nothing have changed.
I think some RF wide lenses could work on the A7/7R, it would just be a coincidence that some lenses works as a byproduct of Sony's design. Yes, it would be fun to finally adopt older RF lenses on a FF sensor that is not a (Leica) rangefinder, but I don't think its optimal.
And to some who commented, that lens x or lens y can work if stopped down to f/8 or f/11, I don't see see this as practical. How many would spend thousands of $$$ on their Leica Summilux to shoot at f/8? Might as well just adapt a good SLR retrofocus lens?
Here's hoping that Ricoh will release a full frame GXR for some of us.
RustyBug wrote:
Until you get south of 25, the need for the mustache doesn't seem that warranted in SLR glass. To me 35mm is not that much wider than normal. Until you get to the 21 (where the King rules @ SLR) and wider, it is much easier to keep the compromises at bay. Do the UWA's (south of 25) use it (mustache) in the M mounts?
rusty – mustache distortion is not a necessary trade off for wides and ultra wide retrofocus lenses, it's just the one that zeiss prefers. other manufacturers choose to accept straight up barrel distortion, which is more obvious in images but also easier to correct these days in post.
+1 @ Zeiss preference toward it. That's their approach to the tradeoffs of optics. Others accept the vignetting or soft corners without employing the mustache. As always ... choose your poison.
RustyBug wrote:
Until you get south of 25, the need for the mustache doesn't seem that warranted in SLR glass. To me 35mm is not that much wider than normal. Until you get to the 21 (where the King rules @ SLR) and wider, it is much easier to keep the compromises at bay. Do the UWA's (south of 25) use it (mustache) in the M mounts?
Well the ZM 21 and 18 do have the mustache distortion, though I don't think it's really visible in actual photos. I've owned the ZM 18 and never really noticed it. You can check the data sheets at Zeiss website.
Thanks Ed ... that could bode well for keeping the angles of incidence in check ... sharing some of the refraction angles more in lens, i.e. less needed at micro-lens.
I've been mostly anti-mustache (as I've chosen Oly's & TS-E's) for FF SLR (my widest Zeiss is 28mm) ... but here I could see it as a viable trade-off @ choose your poison for rangefinder glass. Without it by design, I think the angles will just be too steep @ the micro-lens. If I were looking for rangefinder glass that didn't smear or color shift ... I'd be looking for those with mustache to do better than those without @ UWA.
edwardkaraa wrote:
Well the ZM 21 and 18 do have the mustache distortion, though I don't think it's really visible in actual photos. I've owned the ZM 18 and never really noticed it. You can check the data sheets at Zeiss website.
You're right. Distorsion on Biogons is much less noticeable than on Distagons :
-Biogon ZM 21/2.8 -> must. distorsion = 1% - Distagon C/Y 21/2.8 -> must, distorsion = 2.5%
Someone posted in my review that they tried the Contax G 21mm on both the a7 and a7R, and that results on the R were OK. Unfortunately not much detail provided, but here's the link to the comment.
Edit, sorry, was in a rush and didn't realize the link was specific to me being logged into my site. It's now fixed
Interesting. From what I understand the difference between the very similarly designed Contax G and ZM Biogons are that the rear element protrudes closer to the sensor on the G. Contrary to most here I did think the ZM performed quite ok in your test, at least stopped down.
rscheffler wrote:
Someone posted in my review that they tried the Contax G 21mm on both the a7 and a7R, and that results on the R were OK. Unfortunately not much detail provided, but here's the link to the comment.
wfrank wrote:
Interesting. From what I understand the difference between the very similarly designed Contax G and ZM Biogons are that the rear element protrudes closer to the sensor on the G.
Thing is, the exit pupil doesn't at all have to coincide with the rear element. It often gives a hint though.
Also there is comment about G21mm on A7 and A7R, the result on A7R is OK it says.
Toward the end of this page: [url=]http://bbs.kakaku.com/bbs/10102510055/SortID=16463755/#16733043[/url]
Also he used an electric AF G->E adapter, it worked alright.
I think that this quote is what Ron was referring to that was mentioned on his site; it is a cut and paste:
"golfkidds(Japanese) Says:
October 20th, 2013 at 13:10
10/19-20,at Sony Ginza(TOKYO),I touch and shoot sony A7&A7R with Contax Biobgon21mmF2.8.
resarut was a7B was very good,but A7 was poor. I used AF-adaptor(MXCAMERA),It work very well.
AF is OK,and Exif shows 21mm."
wfrank wrote:
Would you say it is correct to assume the edge of the rear lens element approximately marks the point where the steepest light-ray-angles are found?
I'm no expert, but look into the lens from the rear and check where the aperture seems to be, because that's generally the exit pupil. With a smallish rearmost lens element, the angle should coincide with that from the exit pupil I guess. But with larger rear elements you'll have to look at the design to know.
