RustyBug wrote:
Got my hands on a pair of 24mm lenses.
Tripod shot, same focal point, same aperture (2.8), same exposure, same light (don't let the diff in vignette fool ya).
Note the diff in falloff at the mailbox and LLC. Also, the diff in the amount of ASPH contribution ... same focal length, same perspective (i.e. tripod position).
I also find the aspect of the tree branch TRC acuity, similar to the LLC variance.
Seems to be a pretty big difference in T-stop here despite the same aperture and for me makes comparing the lenses for 3D difficult.
RustyBug wrote:
Got my hands on a pair of 24mm lenses.
Tripod shot, same focal point, same aperture (2.8), same exposure, same light (don't let the diff in vignette fool ya).
Note the diff in falloff at the mailbox and LLC. Also, the diff in the amount of ASPH contribution ... same focal length, same perspective (i.e. tripod position).
I also find the aspect of the tree branch TRC acuity, similar to the LLC variance.
To me the "3D" effect is stronger in the first sample.
My guess it's a prime, maybe a Voigtlaender lens, while the second one might be the Zoom lens that can be seen in the first picture - is it a Sigma?
Before comparing the lenses too closely and attributing different characteristics to them, there is one issue that needs to be addressed:
The lens used for the second image is probably considerably longer than the one used for the first. As a result, the camera–lens system is positioned closer to the subject. This, in turn, means that the foreground in the first image is not stretched apart as much as it is in the second image (try overlaying the images as separate layers in Photoshop, for example).
As a consequence, the foreground in the first image appears slimmer and more elongated, creating a greater sense of depth. It also means that the second image generally exhibits more background blur, simply because the subject distance is shorter.
Therefore, if one wanted to compare these two lenses fairly, the front element would need to be positioned at the same distance from the subject in both cases.
This effect is, of course, particularly noticeable when working close to the subject, because the physical length of the lens then makes a meaningful difference. At greater distances, however, the effect is likely to be much less apparent.
Rob70 wrote:
To me the "3D" effect is stronger in the first sample.
My guess it's a prime, maybe a Voigtlaender lens, while the second one might be the Zoom lens that can be seen in the first picture - is it a Sigma?
Before comparing the lenses too closely and attributing different characteristics to them, there is one issue that needs to be addressed:
The lens used for the second image is probably considerably longer than the one used for the first. As a result, the camera–lens system is positioned closer to the subject. This, in turn, means that the foreground in the first image is not stretched apart as much as it is in the second image (try overlaying the images as separate layers in Photoshop, for example).
As a consequence, the foreground in the first image appears slimmer and more elongated, creating a greater sense of depth. It also means that the second image generally exhibits more background blur, simply because the subject distance is shorter.
Therefore, if one wanted to compare these two lenses fairly, the front element would need to be positioned at the same distance from the subject in both cases.
This effect is, of course, particularly noticeable when working close to the subject, because the physical length of the lens then makes a meaningful difference. At greater distances, however, the effect is likely to be much less apparent. ...Show more →
Yes, the lens length is different, so up front we can see some diff there. In the BG, that diff shouldn't make much difference in the rate of transition to the mailbox, nor the LLC to the ground / TRC to the tree branch ... structurally.
Curious if a reshoot is in the future, should the distance to subject be measured from the front element, or from the lens nodal point ... to account for the lens length diff. Also, given the length of lenses in the SL APO, and Karbe's interest to have the more rapid falloff (even at longer f/2 Cron vs. 1.4 Lux of shorter designs), it strikes me that it "may" be part of the equation for why the BG areas of the longer lens have fallen off more. Not sure, but it did surprise me a bit to see ... and is something I've never given much credence to in the past.
RustyBug wrote:
Yes, the lens length is different, so up front we can see some diff there. In the BG, that diff shouldn't make much difference in the rate of transition to the mailbox, nor the LLC to the ground / TRC to the tree branch ... structurally.
Curious if a reshoot is in the future, should the distance to subject be measured from the front element, or from the lens nodal point ... to account for the lens length diff. Also, given the length of lenses in the SL APO, and Karbe's interest to have the more rapid falloff (even at longer f/2 Cron vs. 1.4 Lux of shorter designs), it strikes me that it "may" be part of the equation for why the BG areas of the longer lens have fallen off more. Not sure, but it did surprise me a bit to see ... and is something I've never given much credence to in the past. ...Show more →
I haven't really looked into this in detail, but it seems to me that it is the entrance pupil—which is often approximated by the center of the front element—that needs to be at the same position for both lenses if one wants to make a truly fair comparison of their rendering characteristics.
The background also appears different because, with the longer lens, the camera is closer to the subject. At the same framing and aperture, this reduced subject distance results in greater background blur.
I would find it very interesting if you could repeat the comparison using the same methodology, but this time ensuring that the distance from the subject to the entrance pupil of each lens is as close to identical as possible. A macro focusing rail might be particularly helpful for achieving the required precision.
Makten wrote:
Very nice! But, isn't there some EFCS bokeh in both those shots? What camera are you using?
I'm debating if i should upgrade my ancient a7 II, but something makes me doubt they have fixed all the flaws, such as this one.
The new A7 V, has a much faster sensor scan speed so in almost all cases you can use the electronic shutter instead of EFCS which basically fixes the issue. So, this one has finally been fixed in the 5th version of the camera.
Makten wrote:
Very nice! But, isn't there some EFCS bokeh in both those shots? What camera are you using?
I'm debating if i should upgrade my ancient a7 II, but something makes me doubt they have fixed all the flaws, such as this one.
Yeah, challenge of being at an air show with the a7R V. I was a little sloppy switching between full mechanical vs EFCS vs ES. When I was switching between my "stuff moving fast" mode to other modes, it reverted back to EFCS. So all on me.
carstenw wrote:
It used to be that eBay listings in Japan and Germany were a question of honour, and you could rely on goods arriving exactly as described and shown, but this has changed now, and you have to really read between the lines, and even then, you might get unlucky.
This could not be more true. I’m convinced some sellers intentionally word their listings with just enough inconsistency to leave themselves a built-in loophole.
The auction title will say something like Mint, Flawless, or Optically Mint. The photos may show glass that looks slightly abnormal, but usually not clearly enough to determine whether it’s fungus, haze, separation, cleaning marks, or something else. Then the description will include vague phrases like:
No scratches “affecting shooting”
But are there scratches or not? And does “affecting shooting” mean it doesn’t affect basic operation, or that it has no impact on image quality?
No tiny dust affecting image
So is there larger dust? Is there dust at all? And whether it affects the image is subjective unless sample images are provided.
No “visible” haze
If it is not visible, then for practical purposes there is no haze. Either haze is visible, or it is not there. That kind of wording just creates ambiguity.
It often feels like the listing is designed to look reassuring at first glance, while still leaving enough room for the seller to say, “Well, we disclosed it,” if there is a problem.
tsdevine wrote:
Yeah, and they'd seem to be all simpler optically (at least in element count).
As I've mentioned the rate of transitions influencing human physiological response cues ... I'm beginning to consider the role of the APO / near-APO in where the starting point in the focal plane is regarding the amount of aberrations present ... as it then transitions into more aberrations territory (kinda your point about element count, as part of the design choices). I don't have it fully vetted, but I think this also falls in line with Karbe's aspect of f/2 design for the SL APO's ... i.e. aberration reduction / transitions ... rate of change variance.
carstenw wrote:
Yeah, Porsche Design did the RTS series, and some other Contax cameras maybe?
They did the OG RTS but I believe the following SLR bodies were local (Japanese) derivations. Porsche Design also did the original Contax T:
Beyond the design accents, this camera is a genuine throwback: drawbridge like a MF folder, removable film back, optical RF, dedicated flash that attaches to the side, no motors.
