cyberstudio wrote:
Well, don't shoot the messenger! There is nothing in the adapter firmware limiting aperture display. An old NEX-3 would for example display F0, but no NEX camera would actually display F0.9.
Sorry can't click on your attachment link. But yes I can see your point about 0.7. No one has ever seen it show 0.9 though and like I said the adapter just pass the max aperture along. It is up to the camera body to display the value correctly, something which we have no control over. If you would like to get it addressed, I would suggest asking Sony instead. Don't be so unfair to the adapter! The adapter is just the messenger.
alundeb wrote:
I have a question regarding the SB on the Canon 50 mm 1.0 L that I have briefly tried.
At wide apertures, there is vignetting as expected. Stopped down to small apertures, the vignetting does not disappear, but becomes a hard limit on the image circle, at about 11-12 mm image height on the APS-C sensor. It is not an issue for me as I do not intend to use that lens with the SB. I am just curious to know what is causing this to happen at small apertures like from f/2.8 all the way to f/11. Thank you for any interest. ...Show more →
The 50/1.0 Canon is a bit of an unusual lens in that it has an extremely long exit pupil distance. According to a patent example I've looked at (Japanese Patent 63-174,008 Example #1 of 2) the exit pupil is located more than 250mm from the image plane. In other words, its a nearly telecentric lens, and this is why there are issues with it on the Speed Booster at small apertures.
The Speed Booster works best with lenses having an exit pupil in the 50-80mm range, which is perfect for compact wide-angle, normal, and some short telephoto SLR lenses. Once the exit pupil distance exceeds ~110mm you'll start seeing "hard" vignetting in the extreme corners at small apertures. Paradoxically, this vignetting is reduced at large apertures because light from the lower portion of the oblique ray bundles strikes the Speed Booster optics at a better angle.
Note that exit pupil distance and focal length are entirely separate and unrelated things.
cyberstudio wrote:
Sorry can't click on your attachment link. But yes I can see your point about 0.7. No one has ever seen it show 0.9 though and like I said the adapter just pass the max aperture along. It is up to the camera body to display the value correctly, something which we have no control over. If you would like to get it addressed, I would suggest asking Sony instead. Don't be so unfair to the adapter! The adapter is just the messenger.
Sorry for the bad link. In the meanwhile I've played around a bit more and found out how to get f/0.9.
Thanks jcolwell also for the dpreview first impressions, interesting reading.
I removed the pin on Olympus 21mm f/3.5 so now it is fitting. Also there is no problem with C/Y 50mm 1/4 & 85mm 1/4 though I have to test them for infinite/daytime focus.
brianc1959 wrote: The Speed Booster works best with lenses having an exit pupil in the 50-80mm range, which is perfect for compact wide-angle, normal, and some short telephoto SLR lenses. Once the exit pupil distance exceeds ~110mm you'll start seeing "hard" vignetting in the extreme corners at small apertures. Paradoxically, this vignetting is reduced at large apertures because light from the lower portion of the oblique ray bundles strikes the Speed Booster optics at a better angle.
Note that exit pupil distance and focal length are entirely separate and unrelated things.
So you're saying with the correct testing and/or calculations, we can have optimal lens models to be used with the SB?
Dudewithoutape wrote:
So you're saying with the correct testing and/or calculations, we can have optimal lens models to be used with the SB?
For example, Zeiss publishes where the exit pupils are in their datasheets. Take the Distagon 21/2.8, for example:
26.2 mm in front of the last lens vertex
and then you add the back focal distance, also in the datasheet.
37.0mm
So 56.2 fits within the sweet spot and it will probably have no vignetting (other than that from the lens itself). Strictly speaking this calculation is not 100% correct because it is not accounting for half the thickness of the rear element (back focus is the distance from the tallest point of the rear element from the sensor plane, so it differs from the last lens vertex by half the thickness of the rear element, a few mm's at most.)
Ok let me stop pretending to be an optical expert now, because I am not... and if I was mistaken I stand corrected in advance
But unfortunately, Canon, Nikon and many others do not publish exit pupil data.
cyberstudio wrote:
For example, Zeiss publishes where the exit pupils are in their datasheets. Take the Distagon 21/2.8, for example:
26.2 mm in front of the last lens vertex
and then you add the back focal distance, also in the datasheet.
37.0mm
So 56.2 fits within the sweet spot and it will probably have no vignetting (other than that from the lens itself). Strictly speaking this calculation is not 100% correct because it is not accounting for half the thickness of the rear element (back focus is the distance from the tallest point of the rear element from the sensor plane, so it differs from the last lens vertex by half the thickness of the rear element, a few mm's at most.)
Ok let me stop pretending to be an optical expert now, because I am not... and if I was mistaken I stand corrected in advance
But unfortunately, Canon, Nikon and many others do not publish exit pupil data.
Very interesting. Certain lens makers will make it a lot easier for us then. Can we project another rise in prices for certain lenses? It so expensive for some of them already.
It's pretty easy to get a fairly good idea of where the exit pupil is. Look in the rear of the lens while holding some pointer like a finger outside the lens and use parallax to locate the pointer and the exit pupil in about the same plane.
cyberstudio wrote:
For example, Zeiss publishes where the exit pupils are in their datasheets. Take the Distagon 21/2.8, for example:
26.2 mm in front of the last lens vertex
and then you add the back focal distance, also in the datasheet.
37.0mm
So 56.2 fits within the sweet spot and it will probably have no vignetting (other than that from the lens itself). Strictly speaking this calculation is not 100% correct because it is not accounting for half the thickness of the rear element (back focus is the distance from the tallest point of the rear element from the sensor plane, so it differs from the last lens vertex by half the thickness of the rear element, a few mm's at most.)
Ok let me stop pretending to be an optical expert now, because I am not... and if I was mistaken I stand corrected in advance
But unfortunately, Canon, Nikon and many others do not publish exit pupil data.
cyberstudio wrote:
For example, Zeiss publishes where the exit pupils are in their datasheets. Take the Distagon 21/2.8, for example:
26.2 mm in front of the last lens vertex
and then you add the back focal distance, also in the datasheet.
37.0mm
So 56.2 fits within the sweet spot and it will probably have no vignetting (other than that from the lens itself). Strictly speaking this calculation is not 100% correct because it is not accounting for half the thickness of the rear element (back focus is the distance from the tallest point of the rear element from the sensor plane, so it differs from the last lens vertex by half the thickness of the rear element, a few mm's at most.)
Ok let me stop pretending to be an optical expert now, because I am not... and if I was mistaken I stand corrected in advance
But unfortunately, Canon, Nikon and many others do not publish exit pupil data.
Actually, the exit pupil distance (measured from the image plane) is 37+26.2 = 63.2mm, which is just fine.
Thanks for pointing out that Zeiss supplied this information in their older data sheets. I never realized that before. Unfortunately, in their new data sheets (e.g., the ZF series) they ignore the exit pupil and only give data for the entrance pupil. Probably because of the current popularity of image stitching.
BTW, the back focal distance is measured from the last lens vertex to the image plane.
brianc1959 wrote:
The 50/1.0 Canon is a bit of an unusual lens in that it has an extremely long exit pupil distance. According to a patent example I've looked at (Japanese Patent 63-174,008 Example #1 of 2) the exit pupil is located more than 250mm from the image plane. In other words, its a nearly telecentric lens, and this is why there are issues with it on the Speed Booster at small apertures.
The Speed Booster works best with lenses having an exit pupil in the 50-80mm range, which is perfect for compact wide-angle, normal, and some short telephoto SLR lenses. Once the exit pupil distance exceeds ~110mm you'll start seeing "hard" vignetting in the extreme corners at small apertures. Paradoxically, this vignetting is reduced at large apertures because light from the lower portion of the oblique ray bundles strikes the Speed Booster optics at a better angle.
Note that exit pupil distance and focal length are entirely separate and unrelated things.
Thank you!
Unlike Canon cameras, NEX cameras with the SB leave the aperture in the closed (stopped down) position when powered down. This makes it easy to see the exit pupil. When I look into the rear of the lens and tilt the lens, I can indeed see that the exit pupil distance is very long.
Mirakaski wrote:
Does anyone know if they plan on making a "dumb" version of the EF to NEX? I saw where someone mentioned a FD to Nex, but not the former.
Unfortunately not. As soon as I saw the price difference between the EF & Leica R version, this was my thought as well. So I e-mailed them and this was their response (my original e-mail below, for reference):
Hi
No, EF will only have existing version
Thanks
Mark
On 15 Jan, 2013:
Hi there!
I've had a look at your new Speedbooster & white paper, looks super interesting.
A quick question:
Do you have any plans on a 'dumb' EF to E-mount (Canon to NEX) Speed Booster? I.e. without autofocus, aperture control functionality.
I'm asking because I plan to use the EF mount as a base for adapting other lenses (e.g Olympus OM, Leica R, Nikon, C/Y) but have no interest in native EF lenses, thus no desire to pay extra for the aperture / AF control I don't need.
