They seem to perform very similarly, except for the maximum aperture. I personally think the 35/2 is the better lens by a small margin. It is the one I have and it's on my Zeiss Ikon 90% of the time. Some people claim it is not sharp wide open, but I think it is a RF calibration problem. Mine was front focusing at close distances, so I sent it to Oberkochen for calibration. Three weeks later it came back focusing perfectly and without costing anything.
I suspect there isn't much of a real world difference. I have the 35 f/2.8 and use it on the M9. It's sharp centrally from wide open, though takes a couple stops for the corners to be perfectly sharp, if that's important to you. On paper the f/2 is nearly distortion free, though the f/2.8 is not terrible here either. At near distances the background rendering of the f/2.8 appears to be a bit smoother and the f/2 version stopped down a couple stops is apparently fantastic for across the frame sharpness at farther distances.
I think it ultimately comes down to whether the difference in cost is a factor for you and whether you will need to work at f/2. If you think f/2 still won't be enough, then I would suggest the Voigtlander 35 f/1.2 II. It's very sharp and has very nice background rendering. BTW, I bought one in Taipei from http://www.cosina.com.tw
I agree with Ron's assessment. My copy is very sharp from corner to corner stopped down to f/4 and smaller. F/2 comes very handy in low light. It is a very usable f/2 not like say f/1.4 on the Z* 50 Planar. Interesting to mention also that this lens has no focus shift whatsoever, which is the main problem of the Sonnar 50.
When I use the Biogon on the GXR-M, the resolving power is just amazing, even wide open at infinity. Absolutely recommended.
IMO a lens must be quite much better to offset the loss of a full stop in speed. ZM35/2 tends to be a bit nervous bokeh wise (wide open at least) close to MFD while sharpness truly excels at further distances, so maybe the 2.8 is better for close-ups?
Remember that lenses perform different at different distances, a fact that some people doesn't take under consideration. That means they will appear to perform different for different styles of shooting, which is why I think some lenses gets mixed reviews on this forum for example.
This thread lacks images so here is one taken at f/4 (I believe) with the ZM35/2, cropped to 5:7. I find the lens to be remarkable sharp, but I don't do pixel peeping and I don't have that many references on this body. I would definitely recommend it.
p.1 #10 · Zeiss ZM Biogon 35/2 or C-Biogon 35/2.8?
well, the c-biogon is quite short compared to it's 35/2 brother, and it's a bit cheaper.
the first can be a valid concern on a rangefinder. on the M2, which is what I use, the 35/2 does block the lower righthand corner. still, it's the one I would personally go for because I find f2 to be good enough for my low light work, and f2.8 would just not be.
p.1 #11 · Zeiss ZM Biogon 35/2 or C-Biogon 35/2.8?
edwardkaraa wrote:
I agree with Ron's assessment. My copy is very sharp from corner to corner stopped down to f/4 and smaller. F/2 comes very handy in low light. It is a very usable f/2 not like say f/1.4 on the Z* 50 Planar. Interesting to mention also that this lens has no focus shift whatsoever, which is the main problem of the Sonnar 50.
When I use the Biogon on the GXR-M, the resolving power is just amazing, even wide open at infinity. Absolutely recommended.
Edward, I did some shot test on my M9 after I acquire the 35mm f2. I found indeed there is very small focus shift. at f2 at MFD, slightly back foucsed and move to f2.8 further f4, focus become spot on.
Since it is small shift and for this focal length AND f2, it may not that obvious.
p.1 #12 · Zeiss ZM Biogon 35/2 or C-Biogon 35/2.8?
zhangyue wrote:
Edward, I did some shot test on my M9 after I acquire the 35mm f2. I found indeed there is very small focus shift. at f2 at MFD, slightly back foucsed and move to f2.8 further f4, focus become spot on.
Since it is small shift and for this focal length AND f2, it may not that obvious.
Thanks for this info, zhangyue. Interesting, because both the ZM f/2 lenses (35 and 50) are not supposed to have focus shift, or it should be so minimal as not to be detectable. However, and I am no expert mind you, what you are describing sounds to me like back focusing not focus shift. If it was focus shift, if the lens is calibrated for f/2, it should be spot on at f/2 and back focus above that. If it is calibrated for f/4, it should front focus at f/2. I will try to find some info about that.
p.1 #13 · Zeiss ZM Biogon 35/2 or C-Biogon 35/2.8?
According to Erwin Puts, Zeiss and Leica calibrate their rangefinders slightly differently, one aiming for the front of the film plane, and the other aiming for the back, so these lenses could possibly work a little better out of the box on the Ikon. Just a thought.
p.1 #15 · Zeiss ZM Biogon 35/2 or C-Biogon 35/2.8?
edwardkaraa wrote:
Thanks for this info, zhangyue. Interesting, because both the ZM f/2 lenses (35 and 50) are not supposed to have focus shift, or it should be so minimal as not to be detectable. However, and I am no expert mind you, what you are describing sounds to me like back focusing not focus shift. If it was focus shift, if the lens is calibrated for f/2, it should be spot on at f/2 and back focus above that. If it is calibrated for f/4, it should front focus at f/2. I will try to find some info about that.
Edward, As you may know that Zeiss lens is optimized for film IKON, thus, it is not surprised to see it is back focus due to different flange distance between Film and Digital M.
(I still suspect my Sonnar actually is benefit from this if it is not optimized at f2.8. I can;t verify if it is optimized for f2.8 to begin with, but my copy seems spot on at f2.8 at MFD.)
It is not back focus. Because I see focus plane move with Aperture. At f2, it back focus, at f2.8 it spot on, and after it, I don;t see any focus plane change any more. Since it is at MFD, I still be able to see focus plane clearly even at f4.
I guess it is small to tell. but I also suspect that is why people complain its WO performance, as it is really not obvious for weak WO from its MTF and from my experience. The reason I did this test is I shoot portrait a lot and require accurate focus on eye at about MFD. Now, I always slightly compensate it for that.
p.1 #16 · Zeiss ZM Biogon 35/2 or C-Biogon 35/2.8?
Zhangyue, thanks again for the info. So the focus shift moves to the front not to the back as you stop down? That is indeed very interesting. I will try to replicate this with my film Ikon tomorrow.
PS: I emailed Zeiss support asking about focus shift with the 35/2. Very interested to see what they have to say about that.
p.1 #17 · Zeiss ZM Biogon 35/2 or C-Biogon 35/2.8?
edwardkaraa wrote:
Zhangyue, thanks again for the info. So the focus shift moves to the front not to the back as you stop down? That is indeed very interesting. I will try to replicate this with my film Ikon tomorrow.
PS: I emailed Zeiss support asking about focus shift with the 35/2. Very interested to see what they have to say about that.
The focus plane move from back to front with aperture stop down. In your film body, you may find it spot on at f2, but front focus stop down. Though I feel it will be challenge to see that for 35mm film, which has equivalent 5-6M pixel
p.1 #18 · Zeiss ZM Biogon 35/2 or C-Biogon 35/2.8?
Hi Zhangyue,
This is the answer from Zeiss:
Dear Mr Karaa,
Thank you for your inquiry to Carl Zeiss.
The amount of focus shift of lenses like the Biogon T* 2/35 ZM is so small that it does not play any role in practical use.
Sincerely,
Bertram Hoenlinger
However, they failed to mention if the focus moves forward or backward as I stop down. I will do my own test even though it will be more difficult to see on film and post the result over here.
