Focus shift is a non-issue for those focusing at shooting aperture in an EVF camera. That's the regular method for many of us, well Taylor and me anyway.
Not to overly criticise the otherwise excellent Lenstip site, but they do not even mention price in their summaries of either the $2000 GM 50/1.2 or the $1400 GM 35/1.4. Why would price be more important a consideration for an $1150 manual focus lens than much more expensive GM pair? Are they suggesting Cosina sell the APO for less? Price is always a consideration for most all of us.
philip_pj wrote:
Focus shift is a non-issue for those focusing at shooting aperture in an EVF camera. That's the regular method for many of us, well Taylor and me anyway.
Not to overly criticise the otherwise excellent Lenstip site, but they do not even mention price in their summaries of either the $2000 GM 50/1.2 or the $1400 GM 35/1.4. Why would price be more important a consideration for an $1150 manual focus lens than much more expensive GM pair? Are they suggesting Cosina sell the APO for less? Price is always a consideration for most all of us.
In my opinion things are not that easy. I find it very challenging to manually focus a wide angle lens at f/5.6 to utmost precision.
But maybe it's just me.
But....if you focus an UWA at f/5.6, you can actually see what will be included with the depth of field at f/5.6...and you can optimize focus for foreground or background, from that spot. (Assuming you're not focusing on a very distance subject.)
If you can't tell what is optimal focusing on a specific spot at f/5.6, that probably means the spot you are focusing on is within the depth of field. You then can assess what in the foreground and background is within the depth of field, if you are focusing at shooting aperture.
If you focus wide open....you optimize for one spot, and depth of field falls where it falls at shooting aperture then.
I traditionally have been focusing wide open, then stop down. I'm trying now more to focus at shooting aperture.
Maximilian wrote:
In my opinion things are not that easy. I find it very challenging to manually focus a wide angle lens at f/5.6 to utmost precision.
But maybe it's just me.
tsdevine wrote:
But....if you focus an UWA at f/5.6, you can actually see what will be included with the depth of field at f/5.6...and you can optimize focus for foreground or background, from that spot. (Assuming you're not focusing on a very distance subject.)
If you can't tell what is optimal focusing on a specific spot at f/5.6, that probably means the spot you are focusing on is within the depth of field. You then can assess what in the foreground and background is within the depth of field, if you are focusing at shooting aperture.
If you focus wide open....you optimize for one spot, and depth of field falls where it falls at shooting aperture then.
I traditionally have been focusing wide open, then stop down. I'm trying now more to focus at shooting aperture.
Though I do not have the new Voigtlander 35mm Apo-Lanthar, and have other Voigtlander lenses including the 50mm Apo-Lanthar Asph in Sony mount, I still normally focus wide open and since my camera is on a tripod will check the markings on the lens for DOF and adjust the aperture accordingly (and stop down a bit more since the markings on the lens are basically for 5" X 7" images). I may still adjust things I want for DOF. I may try your suggested way, but I always thought that I could not get accurate focus when using stopped down focus.
Rich, I've had no problem focusing wide open with the CV 35 (or CV 50.) And I don't have an active subscription to really understand what Lloyd is seeing. I have not really noticed any focus shift in my normal use (where I'm not actively looking if there is some focus shift....just whether the results look good.) Not disagreeing with Lloyd, just hasn't seemed to manifest itself in my shooting as far as I've noticed.
I have been playing around with focusing at shooting aperture though with my MF lenses. It allows me to shoot at a wider aperture and still see exactly what falls within the depth of field of a given aperture. Sometimes I have a habit of stopping down further than I need to, just to make sure that I have everything I want sharp. I've never really been happy with hyperfocal shooting when I've tried it, and I've never really felt comfortable using the markings.
For my waterfall shooting, where I'm using NDs....I still tend to focus wide open as things are pretty grainy stopped down (with CPL/ND.)
So I'm not suggesting it will work better for you, just that I'm starting to dabble with that approach. I haven't to this point noticed anything egregious with focusing wide open and then stopping down when using the CV 35.
naturephoto1 wrote:
Hi Tim,
Though I do not have the new Voigtlander 35mm Apo-Lanthar, and have other Voigtlander lenses including the 50mm Apo-Lanthar Asph in Sony mount, I still normally focus wide open and since my camera is on a tripod will check the markings on the lens for DOF and adjust the aperture accordingly (and stop down a bit more since the markings on the lens are basically for 5" X 7" images). I may still adjust things I want for DOF. I may try your suggested way, but I always thought that I could not get accurate focus when using stopped down focus.
zugzwang2 wrote:
According to the diglloyd test, you can't get accurate focus with the 35mm APO when focusing wide open and then stopping down.
All the infinity tests posted in this review were done by focusing wide open at center, followed by stopping the aperture down to f/2.8, f/4, f/5.6 and f/8 without refocusing.
I've never saw any focus shift with the Voigtlander 35mm f/2 APO E or M-mount. In my experience, focus shift can only be an issue with lenses under corrected for spherical aberration which is not the case here.
Inspect the 100% crops (pixel level) showing center, mid and extreme corners for each aperture sequence and judge the results for yourself. This is my go-to 35mm landscape lens!
Regarding the claim at the diglloyd.com site that the plane of sharp focus changes when the aperture is changed, Fred Miranda wrote:
All the infinity tests posted in this review were done by focusing wide open at center, followed by stopping the aperture down to f/2.8, f/4, f/5.6 and f/8 without refocusing.
I've never saw any focus shift with the Voigtlander 35mm f/2 APO E or M-mount. In my experience, focus shift can only be an issue with lenses under corrected for spherical aberration which is not the case here.
Inspect the 100% crops (pixel level) showing center, mid and extreme corners for each aperture sequence and judge the results for yourself. This is my go-to 35mm landscape lens!...Show more →
Your results are convincing. I've been trying to reproduce Lloyd's results--and I can't.
Firstly, most probably don't know that Lloyd suffers from presbyopia (farsightedness); combine this with the normal age-related decline in vision by your mid-fifties, means that in poorer light, he needs to focus wide open to get accurate focus.
Secondly, there only is ever one plane in actual focus in a 3D image, the rest of the image is out of focus to some degree - the acceptable extent to which depends on how fussy the shooter is, how big you intend to print etc. So, having your main subject intersect with that single plane of actual focus can matter in large prints (simply being within the depth-of-field is not enough to render your subject the sharpest object in the frame), and focusing wide open increases your chances of nailing that focused plane right on your subject (assuming the lens has no focus shift when you then stop down to shooting aperture).
Thirdly, Lloyd also noticed that with the Voigt 35 APO and the Voigt 65 APO, there was some focus creep with the helicoid mechanism when the lenses were pointed downwards for shooting, which may also be 'contaminating' his results.
As to the Lenstip findings - that the 35 APO's performance dropped off faster at close focusing lab conditions at smaller apertures v's the other 35's, I wouldn't read too much into that: I spose its possible that the unique aperture blade mechanism could be worsening diffraction (because the circular-saw shape may increase the surface area of 'edge' the light has to diffract around), but I doubt you'd notice a difference in the real world.
My own copy of the Voigt 35 APO doesn't appear to have any of the above problems either, but I'm probably a little bit less fussy than Lloyd. I am, however, getting randomly overexposed shots: if for example, I focus at f2, then shoot an aperture sequence at whole f stops, touching only the lens to change the aperture, I'm getting an overexposed image - often at f8 or f11. The EXIF data shows the f top as being correct, but there is an anomaly in the shutter speed; i.e. on a cloudless day, you would expect the shutter speed to double for every drop in aperture, but it drops considerable more than that on a single frame within the sequence - and that image is overexposed: any ideas anyone?
Our great new lenses can be (and often are) optimised for wide open performance - at any focal distance - new lenses no longer need to build performance levels over 1-2-3 stops down. And the inescapable corollary of this is a more rapid fall-off into diffraction - which itself is offset somewhat by the very high levels still remaining at smaller shooting apertures.
Putting it in figures to illustrate the point, Leica's SL 35/2 APO gives its lucky users 91% on-axis lens contrast at f2; 82% at f5.6 and 78% at f8 - at infinity. Close focus (0.5m) equivalent figures for the same lens are: 90% at f2; 83% at f5.6 and 78% at f8. (40lpmm data on accurate equipment). The CV 50/2 APO E-mount just barely improves from f2 to f4, same for the 35/2 APO in E-mount.
It's one reason why makers are scrambling to institute full ranges of these lenses within a short timeframe, something that can be expected to continue through these covid years. Except for Cosina, that is, whose lens releases are far more 'center-weighted' around 35 <-> 50mm than the others. They currently sell no fewer than eight lenses between 35mm and 50mm for Sony E-mount, and not one non-macro over that FL - a very unusual situation indeed.
WRT Lloyd: It's hard to expect a man to be equally as fussy as regular photographers when his business model depends entirely on him not being so.
'Presbyopia' (giving a condition a name makes it more prevalent, it's one reason for doing so) IS a normal age-related change:
'A gradual, age-related loss of the eyes' ability to focus actively on nearby objects. Farsightedness usually becomes noticeable in the early- to mid-40s and worsens until around the age of 65.'
Nor does the summary literature suggest a link between farsightedness and dimming of vision or deterioriation in night vision, in healthy individuals.
philip_pj wrote:
WRT Lloyd: It's hard to expect a man to be equally as fussy as regular photographers when his business model depends entirely on him not being so.
'Presbyopia' (giving a condition a name makes it more prevalent, it's one reason for doing so) IS a normal age-related change:
'A gradual, age-related loss of the eyes' ability to focus actively on nearby objects. Farsightedness usually becomes noticeable in the early- to mid-40s and worsens until around the age of 65.'
Nor does the summary literature suggest a link between farsightedness and dimming of vision or deterioriation in night vision, in healthy individuals. ...Show more →
Lloyd's presbyopia is significantly worse than the population mean for his age group.
His reduced acuity in dimmer conditions is normal for his age (separate issue), but can compound his presbyopia.
