Z250SA: do you have a source for CoC of different cameras?
rattymouse: the 25 ist supposed to be not good in the corners at close distance. (field curvature) thats about all there is to it. And it is generally not very well corrected for close distance, it is no macro lens like to 50 or 100 MP, although you can focus it to a few cm from the front lens. Not a good idea to do so wide open.
Hyperfocal distance and aperture settings are NOT the same with different lenses, even at the same focal length and pixel density. For instance, the Z* 35/2 gives a much "steeper" focus fall off than many other lenses, meaning that you have to stop down a bit more and/or focus a little bit further away than usual.
I've actually found that it has a tiny bit of negative focus shift at far distances. It means that at f/8-11 or so, you better set focus AT infinity to get ~4 meters to infinity in focus.
All of this has to do with the correction of spherical aberration for each and every lens. Using Dofmaster is a good way not to have a clue of what you're doing. Just try for yourself, with the lens you intend to use. They all behave differently.
I guess you are right, nothing better than trying yourself. The DOF-master can only be a tool that gets you so far. Especially if the values are wrong. I find it interesting though to play with it. For example that you should get the same dof with 21 @2/8 and 25 @4,0 but 35 @8 (2 steps apart from 25) - but as you say, the results can vary
Ich freue mich, cyra! It´s one of the few joys left in this world of ours, the joy of learning and understanding something new. The computerisation of the photographic art has brought so much new from so many differing fields of both science and art, that very few can master is as a whole. The massive ignorance that rules the internet with small gurus proclaming their supremacy on their own small sites makes it almost impossible for anyone to know whether the "truth" provided is factual or filth.
My own take on HFD is that it may be good for point-and-shooting. When _correctly_ done, perhaps a step further. But as a consequence of what Makten points out, nothing can replace the thorough understanding of the lens you use. The more you lear the more intricate it becomes. But when you bring the best equipment there is out for some serious photography you can, and at some point should, step far further into the art of photography than the HFD-level.
I bought the ZF25 just because it´s mixed reputation when compared to such fascinating images as cyras where, and many others here around. There is apparently much to be learned with this lens!
the 25 is sharper across the field at normal landscape shooting apertures than the 21 and otherwise has no worse performance in every other aspect for typical landscape shooting. the only reason i have the 21 is because sometimes 25 isn't wide enough. if you are doing stuff where you want to shoot nearer wide open or at very close distances then you need to decide how well it works for you. i seldom do either so the 25 is better when i don't need such a wide FOV.
at close distance it has this sweet little extra:
stopping down a bit helps, but watch your background, here it is farther away and thus works out wonderfully.
noch mehr Freude for our multilingual Finn (I agree with you, part of the fun is playing around with it.
Herb, you mean, I don't *need* that so much praized 21 if I have the 25 already?
From what I get from the Zeiss thread, the 21 is a lens that always delivers. That's maybe not true for the 25. You need to avoid a few things with it. But still I am surprized you rate the image quality closed down the same. I always had this feeling of inferiority owning such a lowly lens and not the big great 21. I love it for being small and light (for a Zeiss WA anyway).
Since the thread starter has decided on his lens - should we hijack this thread and give some more attention to the 25? I can dig out a few more, and I would love to see yours, Herb!
my 25 is a sharper lens for typical landscape work at typical landscape apertures than my 21. it's not a large difference but it is there and consistent. i've got a lot of images taken with the 25. i'll pull up a few portfolio ones.
Herb...
cyra wrote:
From what I get from the Zeiss thread, the 21 is a lens that always delivers. That's maybe not true for the 25. You need to avoid a few things with it. But still I am surprized you rate the image quality closed down the same. I always had this feeling of inferiority owning such a lowly lens and not the big great 21. I love it for being small and light (for a Zeiss WA anyway).
Herb, from what I´ve seen around, the opimal f/´s for the 21, as well as for several other Z* lenses are not the old landscape school f/8-16 but rather almost wide open to f/5.6 or f/6.3 at the most. As I started my zeissoholism with the 21 on a crop sensor moving to the 7D, I wanted to avoid any apertures smaller than about f/8 (diffraction) and found out that larger apertures gave very satisfactory results indeed. I remember that fellow forumite Philber had the same experience at the time.
May I propose that you start a new thread on the "25 better than 21" subject. Rocky 1 springs to mind. Such epic battle should get due attention on an arena of it´s own!
cyra, I´m finnlander = mothertongue swedish, not finn = mothertongue finnish. So german ist nich that far away.
Herb, if your 21 isn't extremely sharp, then there is something wrong with it, based on my experience and that of many others. The only thing that might conceivably work against that statement is that it offers so much detail that it can sometimes be mistaken as less sharp than a lens which is less detailed, such as the Z* 35 f:2.0.
this is true for the 25 too. Sometimes sharper then whats good for the image.
Z250SA (whats your name?): Jättebra multilingual nevertheless...
May I propose that you start a new thread on the "25 better than 21" subject. Rocky 1 springs to mind. Such epic battle should get due attention on an arena of it´s own!
me? naa! I don't even own the 21, and can't compare. Why don't you guys who have both of them start it off?
here are some from your motherland for you (Mökelmossen, Öland)
I am sure the 25ZF is a fine lens...the 21mm is superior in the magic donut - the middle 12mm radius, at any aperture that counts. Wide open it is no contest.
The 25mm does very well in its sagittal line for 40 lpmm, but much less for its tangential equivalent, which takes a dive soon after leaving the frame centre.
The 25mm sagittal lines also fall off the cliff at 18mm, so corners suffer accordingly - the 21mm stays stronger out to 21mm from frame centre - the very corner. The 25mm also has a big kick up at near the frame edge, doing no good at all for object shaping - for which flat lines (or at least linear declining) are optimal.
What Herb may be seeing is a 'tidy up' of the two lines out near diffraction limits - but lens softening kills all fine detail in all lenses at that point, and f11 is already quite some way down from peak performance, meaning they all look much the same, by levelling out the better performing lenses.
Virtually all lenses are best at 2 aperture stops down from wide open, which is why CZ report them thus in MTF charts - f5.6 for these two lenses. Diffraction is nudging for even 24Mp FF sensors at f11. I try to shoot at f8 for lenses this wide. See denoir's notes on the extended DOF of the 21mm also. Unless you photograph mounds exclusively, I see some linear distortion in these shots, cyra, much less an issue than the 21mm's, granted!
Your analysis of the MTF is very clear but in real life, the 25 is spectacular at long distances. I understand what Herb is saying. Actually the performance of both lenses is very similar for landscapes, but since the 21 is wider, it may give the impression of lower resolution, since it has to resolve much smaller detail.
Cyra - I love that second shot, the tonality is supurb and the 3d rendering or pop whatever you want to call it makes that bush in the foreground pop.
I'm very much trying to get hold of a 25mm ZF1 to use on my 5D as I want something in the 25-28mm range. I have the much rated Leica 28 v2 but it's performance is dependant on very tight adapter tolerances and I haven't yet managed to get the best from it. The ZF25 with Rayqual adapter (already purchased) may be an easier solution. FWIW I also have the ZE21, ZE35 and ZE50P.
johnahill wrote:
I'm very much trying to get hold of a 25mm ZF1 to use on my 5D as I want something in the 25-28mm range. I have the much rated Leica 28 v2 but it's performance is dependant on very tight adapter tolerances and I haven't yet managed to get the best from it.
Why don't you get a Leitax mount for your Leica 28, John? I tried the ZF25 on my 5D and while it was good, I didn't like the wider FOV which also makes details appear smaller and being less resolved than with an 28mm.
I like the close-ups that I have seen from the Z*21 more than those from the 25, btw.
I've got it on a Leitax adapter, but the leitax is too thin.
I'm currently trying some shimming options but seems to be a lot of bother, i'm now used to the easy way of life with ZE lenses ;-)
Oh, that's disappointing, considering the price of a Leitax mount.
FWIW: I tried the ZF25 on a Fotodiox Pro adapter and it couldn't mount solidly. It had quite a lot of rotational play, which was very annoying. Nikkor lenses mount perfectly solidly to the same adapter... Another thing that I didn't like about the ZF25 is the recessed aperture ring. It's just not very easy to get a good grip on it. I like the ergonomics of Contax lenses so much better in that respect.
philip_pj wrote:
Unless you photograph mounds exclusively, I see some linear distortion in these shots, cyra, much less an issue than the 21mm's, granted!
you are right, there is distortion, but I only realized yesterday that it is actually also shaped like the 21's: it has a moustache-shaped distortion. Maybe not as strong. You can see on these images that it curves back up again at the far sides.
I haven't got my PP toghether right now (can't decide whether to buy Lightroom3 or Capture One), therefor I didn't correct it, since I am at the moment running on a free trial version of Capture One, which unfortunately hasn't included the keystone correction tool nor any lens profiles.
In this context: has any of you found a good tool to correct distortion? I found that in Lightroom the lens profiles where overdoing it, or didn't work that well for other reasons.
Johnahill: thank you. I find myself shooting against the light with the 25 often. It has so little flare. Results can be a bit harsh at times, it definately has high contrast.
I saw quite a few 25 ZF1 go out over e-bay for around 500 € or less.
I find it interesting though to play with it. For example that you should get the same dof with 21 @2/8 and 25 @4,0 but 35 @8 (2 steps apart from 25) - but as you say, the results can vary 
(I agree with you, part of the fun is playing around with it. 
and not the big great 21. I love it for being small and light (for a Zeiss WA anyway).