Ripolini wrote:
I rounded FL to the second significant figure. The decimal has no sense. Actually, lens manufactures never give FLs with a decimal figure
Sometimes manufactures do report the focal length to the tenth of a mm. Zeiss does in many of their data sheets which was often different from what was printed on the lens, which was rounded (usually appropriately) to the nearest 5mm (ultrawide angle lens are typically rounded to the closest 1mm).
If one wanted to be precise, (which is probably overkill) if Voigtlander is measuring the angle of view properly and rounding appropriately the 40 f/1.2 is between 41.2 and 42.0mm in focal length. Because they provide more precision (an extra decimal point) in measurement of the angle of view of the 50 f/1.2, then the focal length should be 49.2mm. So no, they don't round to the closet mm when reporting the focal length of the lens, but they do round to the nearest 5mm, which is exactly what manufacturers have done for a long time with focal lengths close to normal.
Steve Spencer wrote:
Sometimes manufactures do report the focal length to the tenth of a mm. Zeiss does in many of their data sheets which was often different from what was printed on the lens, which was rounded (usually appropriately) to the nearest 5mm (ultrawide angle lens are typically rounded to the closest 1mm).
Yes. I know. You're referring to this kind of data sheets:
Steve Spencer wrote:
If one wanted to be precise, (which is probably overkill) if Voigtlander is measuring the angle of view properly and rounding appropriately the 40 f/1.2 is between 41.2 and 42.0mm in focal length. Because they provide more precision (an extra decimal point) in measurement of the angle of view of the 50 f/1.2, then the focal length should be 49.2mm. So no, they don't round to the closet mm when reporting the focal length of the lens, but they do round to the nearest 5mm, which is exactly what manufacturers have done for a long time with focal lengths close to normal....Show more →
You know, when I write 41 mm (or 42 mm) I mean that the uncertainty is of the order of the mm (+/- 1 mm, or even more).
What manufactures round to the nearest 5mm (with few exceptions, see the Zeiss data sheet above) is the FL at "infinity". They rarely tell to their customers the FL at "real", finite distances, i.e., when the subject is photographed with a size > 0 (mathematically, a subject at infinite distance is not visible in the image).
Therefore, coming back to the Voigt 40/1.2, how does its AoV (and FL) change with distance? Who knows?
And how does change the AoV of the 50/1.2 in real shooting conditions? Comparing AoV and FL at infinity only could not provide the answer to the question: Is it worth getting both 40/1.2 and 50/1.2?
This is especially true for macro lenses. Why advertise that a "macro" lens has a 105 mm focal length if it's actual FL at 1:1 is a mere 50 mm??
I guess not all people buying a modern macro lens are aware of what they get home.
Sep 17, 2023 at 01:14 PM
Steve Spencer Offline • • • • • • • Upload & Sell: On
You know, when I write 41 mm (or 42 mm) I mean that the uncertainty is of the order of the mm (+/- 1 mm, or even more).
What manufactures round to the nearest 5mm (with few exceptions, see the Zeiss data sheet above) is the FL at "infinity". They rarely tell to their customers the FL at "real", finite distances, i.e., when the subject is photographed with a size > 0 (mathematically, a subject at infinite distance is not visible in the image).
Therefore, coming back to the Voigt 40/1.2, how does its AoV (and FL) change with distance? Who knows?
And how does change the AoV of the 50/1.2 in real shooting conditions? Comparing AoV and FL at infinity only could not provide the answer to the question: Is it worth getting both 40/1.2 and 50/1.2?
This is especially true for macro lenses. Why advertise that a "macro" lens has a 105 mm focal length if it's actual FL at 1:1 is a mere 50 mm??
I guess not all people buying a modern macro lens are aware of what they get home.
Although we don't know the exact focal length at closer focus distances, lenses typically do not change much from 1:6 or 1:8 magnification to infinity. We see that in the two Zeiss lenses in your table. Since the Voigtlander 40 f/1.2 has a max magnification of 1.6.2 and the 50 f/1.2 has a max magnification of 1:7, we can be fairly confident that through their whole focussing distance they won't deviate much from the 41 to 42 mm for the 40 f/1.2 and the 49mm with the 50 f/1.2. Is that different enough for one to want both lenses? That, IMO, depends a lot on the specific user. For me, I decided I didn't want both but others could certainly make a different decision.
Steve Spencer wrote:
Although we don't know the exact focal length at closer focus distances, lenses typically do not change much from 1:6 or 1:8 magnification to infinity. We see that in the two Zeiss lenses in your table.....
It depends on the specific lens. Focus breathing affected substantially the Nikkor AF-S 70-200/2.8G VR II at the long end: FL changed from 200 mm, at infinity, to 138 mm at the MFD (-31%). Moreover, if we look at the data I plotted above, we see that the Nikkor Z 105/2.8 MC changes FL from 102,9 mm at infinity to 91.4 mm at 1:6.43 (-11%), while the Nikkor AF-S 105/2.8G VR changes FL from 103.97 at infinity to 103.51 mm at 1:6.55 (- 0.54%). With no information, we can't draw any meaningful conclusion.
Sep 18, 2023 at 01:22 AM
Steve Spencer Offline • • • • • • • Upload & Sell: On
Ripolini wrote:
It depends on the specific lens. Focus breathing affected substantially the Nikkor AF-S 70-200/2.8G VR II at the long end: FL changed from 200 mm, at infinity, to 138 mm at the MFD (-31%). Moreover, if we look at the data I plotted above, we see that the Nikkor Z 105/2.8 MC changes FL from 102,9 mm at infinity to 91.4 mm at 1:6.43 (-11%), while the Nikkor AF-S 105/2.8G VR changes FL from 103.97 at infinity to 103.51 mm at 1:6.55 (- 0.54%). With no information, we can't draw any meaningful conclusion.
You are giving examples of macro lenses and zooms with fairly short MFD. I don't think you will find examples of normal primes with 1:6 or 1:8 maximum magnification that show anything like what you are describing.
Because of the kids, I ended up buying an AF fast 35mm lens. I love my 40 1.2, and if I have the time to MF it produce stellar images, also it's another level the procedure of taking picture, composing, focusing, I feel lot more connection, more photography. But I've just taken my ZF 35 2.8 more and more for family pictures because of the AF. So I decided to get a used prime for a try, I hesitated between 35GM and 35 1.2 Art. I found an Art significant cheaper than GM (it is very popular lens, barely found here a used and it's gone after few days), also after the Voigtlander I'd always have a desire for that f1.2 bokeh.
So I got the 35 1.2 Art, my first impression was it is damn huge lens, my 40 1.2 simply dwarfed compared. I took it quickly to take some pictures. No need to look into EVF, no need for rotating focus ring, moving joystic to hunt for my constantly moving daughter's eye. Eye-tracking AF just works.
Beside AF, I simply blown away from image quality. It's an insane lens, razor sharp at 1.2, still has butter smooth bokeh. I amazed how good optically, better than 40 1.2 in every aspect, it's like MF images with paper thin DOF and sharp corner to corner, barely visible CA and high contrast. I'm considering to sell the Voigtlander (however I still in love), also I want to pass 21 3.5 skopar, 15 4.5 (barely using this focal length), Samyang 75 1.8 and rebulid my kit with the 35 1.2, Voigt. 21 1.4 and 85 1.4 Art. Anyway I wonder if anybody moved from 40 1.2 to 35 1.2 Art, and what was the long term impression.
patotts wrote:
Now how do you get your wife to stand still and smile for a photo? I've been trying for 20+ yrs ;-)
Trying to get your wife of 20+ years to stand still, or still searching, after 20+ years, for such a wife?
Well, in my case, I found a wife who was already a serious photographer, before I met her. She does not, however, want me to post images of her, that are publicly viewable, so, the problem still exists, just on a different level. Notably, she was the one who finally convinced me to become serious about photography. Until then, I was more into nice binoculars. She expanded my interest toward interchangeable-lens cameras, though it took some time, and I expanded her photographic interests to include birds, wildlife, native plants, and nature, in general.
Notably, my girlfriend, before I met my future wife, had primed me to like female photographers. This girlfriend was already artistic, in several mediums, but could not afford a serious camera. I bought her a better camera. I hope that she is still being creative, today…
This must be one of the longest threads here, on FM forum, and I guess this lens just deserves it.
Sure enough, I went through all these pages before committing to buy the SE version of this lens.
Then, after being underwhelmed by the A7C II/R releases, I finally decided than I can manually focus this lens on my A7C, and the Nokton can be part of my lightweight travel kit alongside Sigma 90i.
Therefore, I would need an AF fast lens for when AF is needed (not that often, though) in this "normal" focal range, and my very first option was set for the 50/1.2 GM which I liked a lot for the brief period of time when I had it.
So if there is someone who own/have owned both those lenses and would care to write few words here about how they compare, that would be much appreciated. I guess the GM lens' price is what actually makes me give it another thought and hold me back of just purchasing it given it won't see much use actually (only for when I need to chase "moving targets", which is not that often for me).
