From what I saw in Ron's shots it would not look good. OTOH some reported the Leica Elmar 24, Leica Elmarit 28 pre-asph or the Leica ASPH Summicron as being very good on the A7, so I still have hope, even if the G28 not so good is ( that is I would not buy it as it stands ).
RustyBug wrote:
12mm @ f16 (12mm/16 =.75mm) is going to be an extremely small physical aperture (diffraction inducing) ... I think a pinhole camera probably uses a larger aperture than that.
The diffraction from a 12mm lens at f/16 will be exactly the same as the diffraction from any other lens at f/16. Really, I know we were unable to convince you of this, but it's a fact.
The wavelength of light is in the nanometers. You can fit a thousand or so wavelengths across a 0.75mm aperture.
douglasf13 wrote:
Are you talking out of camera jpegs or raw? Isn't there some new jpeg sharpening algorithm in-camera that somewhat counteracts diffraction?
Sorry I mixed things up a bit. The CV 15/4.5 is at its best @ F16 in my test; and I'm talking about sooc jpegs:
The truth is slowly seeping out. This thread is now infamous worldwide
I think we need another two weeks--maybe a month, then I will start the "The REAL WA RF A7(r) performance thread", where normal shooters might find some useful info to measure against their expectations.
I'm seeing some nice images from lenses I had written off.
No sense in doing it yet, because it's too early. We need more good shooters trying to make their wides work and experimenting.
No doubt a new thread will cause a furor, but some self selection in participation may be a plus.
Taylor Sherman wrote:
The diffraction from a 12mm lens at f/16 will be exactly the same as the diffraction from any other lens at f/16. Really, I know we were unable to convince you of this, but it's a fact.
The wavelength of light is in the nanometers. You can fit a thousand or so wavelengths across a 0.75mm aperture.
Yes you can fit many wavelengths through a .75mm aperture ... and you can fit more than 4X as many wavelengths through an aperture that is more than 2X as wide. The proximity of opposing/adjacent edges are closer to each other, wave amplitude will be stronger at closer intersections than at more distant ones. Think about two boats passing each other more closely vs. farther apart. The rise/fall of the intersecting wave amplitude will be more pronounced for the wake of the two boats that are closer together than those originating farther apart.
But, as you say ... I know I'm unable to convince you of this.
shelt wrote:
Here's an infinity test of the a7 and Leica 35mm Summilux ASPH FLE (on a crummy adapter that focuses well past infinity). It's my best imitation of Phillip's approach
Remember, the Lux 35 wasn't really meant to be a planar landscape lens, but I really like it for that. Click through to flickr for the pixel level image. No corrections for color or vignetting were made. Keep in mind it's still very hazy here, so the low contrast is due to that. I've found all falloff easily correctible with the flat field plugin. The "Overall Scene" at the bottom is f/8 with minor falloff corrections.
Wow, that is just shockingly good by f5.6. Tim Ashley has said that the 35 lux fle + A7r outperforms his Sigma 35+d800e for landscape. i had a hard time believing it,but stopped down, it definitely seems to at least be in the ballpark.
RustyBug wrote:
Yes you can fit many wavelengths through a .75mm aperture ... and you can fit more than 4X as many wavelengths through an aperture that is more than 2X as wide. ...
RustyBug,
your observations are right, as long as you only look at the behaviour of light at the physical aperture. What you fail to realize is that the "deviation" of the light (as a particle) is angular, thus the effects in the image plane (and those are the ones we're interested in ultimately) are dependent on the (optical) distance of the aperture from the image plane. Of two (simple) lenses with the same physical aperture size, the one with the longer focal length will have a greater distance between the aperture and the image plane, thus creating a greater linear deviation of light in the image plane despite both apertures having the same angular diffraction effect.
Because of this angular component that you didn't take into account, the effect of the physical diameter of the aperture is cancelled out and only the f-number is what matters when looking at diffraction effects in the image plane.
p.124 #10 · A7/A7r - performance with WA RF lenses
dcjs wrote:
Because of this angular component that you didn't take into account, the effect of the physical diameter of the aperture is cancelled out and only the f-number is what matters when looking at diffraction effects in the image plane.
Gotcha at distance to film plane impacts the strength of wave amplitude (3D trig vs. 2D trig) and that the distance across the physical aperture is not the only factor. Would be curious to see the full calculation for a 24mm @ f16 vs. 12mm @ f16 ... at the film plane (+1 @ where it matters) to reveal how it offsets or varies. If the offset exists that I'm missing, I can gladly be convinced ... I just need to see it in formulaic form so I can better foster the understanding and/or recognize what I've missed.
Do you have a good link or can illustrate the trig/math formulaic calculations that illustrate the offset that is suggested I'm missing? Also, as indicated that the optical distance to film plane is involved, would that not additionally correlate that the placement of the physical aperture distance from the film plane impact the magnitude of the diffraction wave amplitude (at the film plane) ... noticeably different in say a 12mm vs. 300mm lens with each @ f/16. Thinking about the f/64 club ... if everything "offsets" such that only the f-stop matters at all (numerically given) f-stops are the same, then wouldn't the amount of diffraction for f/64 be undesirable (unless the wave amplitude is decreased over the greater distance from the physical aperture to the film plane).
Which raises a question @ RF glass vs. SLR glass, to wit: does being closer to the film plane impact the amount of diffraction (for a given FL/aperture) at the film plane in the center and/or the edges/corners even though both are covering the same 24x36 format (i.e. does an M @ f/16 yield more/less/same diffraction as an R @ f/16)?
p.124 #11 · A7/A7r - performance with WA RF lenses
RustyBug wrote:
Do you have a good link or can illustrate the trig/math formulaic calculations that illustrate the offset that is suggested I'm missing? Also, as indicated that the optical distance to film plane is involved, would that not additionally correlate that the placement of the physical aperture distance from the film plane impact the magnitude of the diffraction wave amplitude (at the film plane) ... noticeably different in say a 12mm vs. 300mm lens with each @ f/16. Thinking about the f/64 club ... if everything "offsets" such that only the f-stop matters at all (numerically given) f-stops are the same, then wouldn't the amount of diffraction for f/64 be undesirable (unless the wave amplitude is decreased over the greater distance from the physical aperture to the film plane). ...Show more →
f/64 club? Large format I guess. Diffraction appears at all apertures, but it becomes limiting for your system when the resolving power of the lens+aperture is lower than the resolving power of the sensor/film. With large format, low resolving power isn't a problem, because you don't need to need enlarge the picture as much as with full frame.
p.124 #13 · A7/A7r - performance with WA RF lenses
alwang wrote:
Wow, that is just shockingly good by f5.6. Tim Ashley has said that the 35 lux fle + A7r outperforms his Sigma 35+d800e for landscape. i had a hard time believing it,but stopped down, it definitely seems to at least be in the ballpark.
That's interesting. I'll have to take a look at Tim's test. There's an old post where Luka showed the significant Zone B dip of the 35 Lux on the M9 at infinity, so I'd imagine that to still be an issue (Luka prefers the ZM 35/2 for distant landscapes.)
Nov 29, 2013 at 03:18 PM
Steve Spencer Offline • • • • • • • Upload & Sell: On
p.124 #14 · A7/A7r - performance with WA RF lenses
douglasf13 wrote:
That's interesting. I'll have to take a look at Tim's test. There's an old post where Luka showed the significant Zone B dip of the 35 Lux on the M9 at infinity, so I'd imagine that to still be an issue (Luka prefers the ZM 35/2 for distant landscapes.)
I think Luka had the non-FLE 35 Lux ASPH though. The newer FLE version is quite different.
p.124 #15 · A7/A7r - performance with WA RF lenses
douglasf13 wrote:
That's interesting. I'll have to take a look at Tim's test. There's an old post where Luka showed the significant Zone B dip of the 35 Lux on the M9 at infinity, so I'd imagine that to still be an issue (Luka prefers the ZM 35/2 for distant landscapes.)
At the end of my test (page 123), I posted the full image and a link to flickr (6000x4000 version is there).
p.124 #16 · A7/A7r - performance with WA RF lenses
Here's another test -- the a7 with the Leica 24 Elmar-M ASPH f/3.8. As you may know, this is a fantastic sharp and contrasty lens, but has smearing issues on the a7 and a7r. I love its resolution, contrast and micro-contrast, so I wanted to see if it usable on the a7. Depending on subject matter, f/5.6 may work. f/8 is pretty decent at the edges and ~OK in the corners; f/11 doesn't appear to lose much to diffraction (there are a couple of places I can see minor degradation), and the corners are much better. Overall, this looks better than my other WA SLR lenses for 24mm, so I think it will do for now... Click on the Flickr link to get to the full sized version.
p.124 #19 · A7/A7r - performance with WA RF lenses
With all this talk of the thicker sensor glass causing/inflating these WA RF problems, has anyone considered http://www.maxmax.com and their sensor glass replacement and conversion services?
p.124 #20 · A7/A7r - performance with WA RF lenses
theSuede wrote:
So you've seen what the A7R would do if it had microlenses with less offset? Because that's what's it's all about... Not that the smaller pixel camera would in any way be better than the larger pixel camera (in this case).
There's a huge difference in pixel structure height vs active pixel aperture width between the A7 and the A7R. Unless they added more offset, the difference in color shift would be even bigger.
So I do think you're missing the point here, totally.
Puckat, seriously. It should to be awkward to bring a statement out of context and call it rubbish, then repackage it and state it as your own. Sometimes you need to climb down that tech pedestal of yours and focus on imagery.
Or, if the it was not as blunt or deliberate as it seem, go read the OP.
