Benjamin Marks
Mentor
Folks:
In a recent thread, I stated that my C/V 50 Heliar f/2 was a little soft open, but improved much stopping down. I took some test pictures this morning and I'd like to qualify that. Although the performance of this lens takes a _marked_ jump at f/4, the quality at f:2 is acceptable -- it is really a lens whose character changes as you stop down and in this the image quality is a little that of a Sonnar, which can be quite dreamy wide open but sharper as you move through the range. Note the slightly "gauzy" quality of the hair in picture 1, vs. picture 3.
Here are three shots (f:2, 2.8 and 4) cropped at 100%. Focus was on the iris of the eye. I can count the eyebrow hairs in the f:4 shot (quality reminiscent of MF). Camera: M8, set to ISO 160, on a tripod, UV/IR cut filter on the lens, conversion resolution set at 300 ppi, but I don't know what RFF will do to that. Images were converted to 16 bit Tiffs in PS3 at 300 ppi using Camera Raw and then down-sized to 8-bit jpgs to post to RFF. No sharpening applied.
In the second post in the thread is the whole file with the lens at f:2 at 72 ppi so you can see that the quality is fine with the lens wide open.
Here's to all you Sunday morning pixel peepers out there. I should say that in the down-sizing and conversion to jpg (even at minimum compression) a little 'bite' is lost from the resolution of all these images as they appear on my screen. But I think, having looked at the post, that you will get the general idea from the pictures.
Ben Marks
In a recent thread, I stated that my C/V 50 Heliar f/2 was a little soft open, but improved much stopping down. I took some test pictures this morning and I'd like to qualify that. Although the performance of this lens takes a _marked_ jump at f/4, the quality at f:2 is acceptable -- it is really a lens whose character changes as you stop down and in this the image quality is a little that of a Sonnar, which can be quite dreamy wide open but sharper as you move through the range. Note the slightly "gauzy" quality of the hair in picture 1, vs. picture 3.
Here are three shots (f:2, 2.8 and 4) cropped at 100%. Focus was on the iris of the eye. I can count the eyebrow hairs in the f:4 shot (quality reminiscent of MF). Camera: M8, set to ISO 160, on a tripod, UV/IR cut filter on the lens, conversion resolution set at 300 ppi, but I don't know what RFF will do to that. Images were converted to 16 bit Tiffs in PS3 at 300 ppi using Camera Raw and then down-sized to 8-bit jpgs to post to RFF. No sharpening applied.
In the second post in the thread is the whole file with the lens at f:2 at 72 ppi so you can see that the quality is fine with the lens wide open.
Here's to all you Sunday morning pixel peepers out there. I should say that in the down-sizing and conversion to jpg (even at minimum compression) a little 'bite' is lost from the resolution of all these images as they appear on my screen. But I think, having looked at the post, that you will get the general idea from the pictures.
Ben Marks
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Benjamin Marks
Mentor
And here is the full picture. I have pledged to myself that I will not take any more pictures of my children watching television. But Sunday morning cartoons is about the only time my son is not in full motion and this, I tell myself, was a lens test and so does not break the rule.
Ben Marks
Edit: What I should have been explicit about is that there is nothing in the f:2 portrait that would keep me from using it or printing it. The overall feel of the picture is a little softer than the f:4 image, but to my eye not offensively so. I guess it depends on the look you are going for.
Ben Marks
Edit: What I should have been explicit about is that there is nothing in the f:2 portrait that would keep me from using it or printing it. The overall feel of the picture is a little softer than the f:4 image, but to my eye not offensively so. I guess it depends on the look you are going for.
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ljsegil
Well-known
Very nice work, very instructive. I agree with you that the wide open Heliar does share some of the imaging characteristics of a good Sonnar, but of course the Heliar/Dynar lenses are longstanding classics for portraiture in their own right. Your demonstration of the marked improvement in detail at f/4 is revelatory. A question for the gurus: What makes a lens a good portrait lens, rather than simply being a lens that does not focus quite sharply at larger apertures? I think the difference is more than semantic. Roger, others, thoughts and wisdom?
Larry
Larry
Benjamin Marks
Mentor
For my part, the subject chooses (or helps choose) the lens. The lens I choose for a woman of a certain age is more likely to treat fine details kindly (50 Summarit, Canon 50/1.5, 50/2 Summitar) when wide open. I would put the 50/2 Heliar in this camp. I am not a lens guru, but I associate this with uncorrected coma when the lens is wide open -- it may in fact be one of the other common aberrations. The lens that I choose for a child's portrait will likely be more highly corrected when wide open (e.g. 90/2.8 Elmarit, 50 Summicron etc., or even Nikon's supurb 105/2 DC (with the "defocus" set to neutral)).
Ben
P.s. Anyone who uses the the word "revelatory" with respect to any post of mine is alright with me.
Ben
P.s. Anyone who uses the the word "revelatory" with respect to any post of mine is alright with me.
Juan Valdenebro
Truth is beauty
Thanks for that, Ben. Very interesting lens, of course!
ferider
Mentor
Seems like the lens front focuses. Check the button of the sofa.
A good Sonnar is sharper in the center. The Heliar should be too (see Raid's recent tests). It's the resolution in the corners that make the difference.
A good Sonnar is sharper in the center. The Heliar should be too (see Raid's recent tests). It's the resolution in the corners that make the difference.
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raid
Dad Photographer
An issue to consider when testing a lens is the fact that usually a RF camera is used without a tripod. So when a lens is "good enough" when used with a tripod, the observed sharpness/resolution will be lower when hand holding the camera. I am always surprised how sharp lenses appear when I use a tripod with the camera. If sharpness is needed and if the photos will be taken hand held, it may be a good idea to also try the lens out hand held and compare. What you get in sharpness hand held is what you will get.
Benjamin Marks
Mentor
Ferider's comment is a good one, I hadn't focused on the fact that there might be other issues rather than the pure resolving power of the lens. Focus was careful though, so perhaps this is another factor to consider when reaching for this lens.
Ben
Ben
Benjamin Marks
Mentor
I have had another look at the original file. The difficulty with assessing the possibility that ferider brings up is that the camera was on a tripod, pointed down (say 35 degrees) at my son. He was lying on the couch and the camera is pointed at him from an angle below his chin. There is indeed a portion of the couch in front of the button on the f:2 image that is in critical focus. But because of the camera's tilt the plane of focus in the image runs at a corresponding angle through the 3-D scene, I can't really tell whether his eye is in the zone of critical focus or not. His right eye is pretty much in focus, but I think I will have to make a different controlled test to see whether front focus is an issue.
Ben Marks
Edit: note that there is a "glow" to the fine detail (e.g. hair) in the OOF areas. This is certainly a quality that the lens has wide open and not an artifact of front focus.
Ben Marks
Edit: note that there is a "glow" to the fine detail (e.g. hair) in the OOF areas. This is certainly a quality that the lens has wide open and not an artifact of front focus.
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ljsegil
Well-known
I wonder if anyone following this thread has had the opportunity to directly compare the 50/2 Heliar with the 50/1.5 ZM Sonnar?
Larry
Larry
Tom A
RFF Sponsor
Larry, I have both (50f2 Heliar and Sonnar 50f1.5) - they are different in my opinion. The Sonnar is a great all-rounder with good wide-open performance - the Heliar has a distinctive "look" at f2 - soft, glow in highlight edges. Both a sharp - but they do look different in the final image.
I will see if I can do a direct side-side run of some of these lenses in the next while. There is still some tech Pan spooled up and also some of the Minicopy II in my filmbox.
I will see if I can do a direct side-side run of some of these lenses in the next while. There is still some tech Pan spooled up and also some of the Minicopy II in my filmbox.
Juan Valdenebro
Truth is beauty
Ben, the f/4 shot really looks like medium format... I wonder if you find other 50s usually as sharp as this one... Maybe it's my screen, or maybe I should stop down my lenses more frequently, but it looks like that shot would be great for a big print... Now that I came back to see the shots again, I was surprised because I thought you used a film camera... And if you say there was no sharpening... Impressive quality lens and camera...
Benjamin Marks
Mentor
My 50 Summilux Asph, the C/V 50/3.5 Heliar, the 50 Summicron (80's) and 50 Planar all exhibit this level of sharpness when stopped down to f:4. The 50 is my favorite all-around lens and I have different examples from different manufacturers - officially more 50's than anyone needs. My current "glow" favorite is an old collapsible 50 Sonnar, which I am still learning how to use. It appears to be uncoated and I am using it on an M8 with an adapter. As mentioned above, a 50 Summarit, 50/1.5 Canon and 50 Summitar also have a very nice feeling to them wide open, with the Summitar being the sharpest of the three.
Ben
Ben