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You have to set the aperture fixed in your camera to "1.0" and use Av mode. Then, the camera sets the right speed for the aperture you set manually in the lens. Since the manual lens were designed for 35mm film, smaller sensors like the Foveon X3, trend to overexpose when the lens is wide open due to the parasitic light going around the sensor. Some people is doing some kind of "jackets" on their lenses to reduce the diameter of the back lens.
Regarding the Autofocus, I understand you mean the focus confirmation, because there is no way to autofocus with manual focusing lenses...
Not sure how it does work. On other cameras, like the Canon or the Olympus, there are "chipped" adapters that mimic the behaviour of the AF lenses for this. I haven't seen any chipped adapter for the Sigmas, this might be for one of two reasons: Either it's supported by the camera with no chips (like in the Pentax) or there is no way.
I'll be trying it on my SD10 to see what happens with the M42 ones (I cannot recall it at this time).
What I have found in both the Leica-R conversation and Nikon-F that I play with...in Aperture-Priority the focus indicator comes on about 40% of the time...with about a 50% chance of working correctly...
I have gone back to the two eye method....you keep both eyes open...and focus thru the viewfinder....
This being said...with my Ziess 1.4/50 and 1.4/85 my focus indicator is right on...do what Jes said...set the aperture to 1.0 in Aperture-Priority...and see what happens...I have not had as good of a success with my Leica-R lenses..
the aperture 1.0 setting works good in most cases.What I experienced are
other problems even with optically really good fullframe manual lenses:
+ heavy CA (chromatic abberations)
+ often difficult to judge the right focus point with the SD14 matte screen
(esp. in low light situations)
+ lenses are more prone to backlight reflections
(than newer Sigma DG lenses) which decreases
overall image contrast and makes it appear less sharp and soft
+ AF viewfinder indicator often wrong w.manual lenses due to
back or frontfocus shift from manual lens adapter (e.g. M42 ring)
stick to newer Sigma DG AF lenses - best quality and usable AF !
no real advantage using expensive Zeiss or comparably excellent manual lenses on a SD14
fixed lenses ALWAYS look better than zoom lenses
On the SD14, in Manual Mode:
Select the desired shutter speed by rotating the â€œCâ€ dial. Then hold the +-AV button at the back of the camera to select the desired aperture by rotating the â€œCâ€ dial.
In A mode (priority to Aperture):
Rotating the â€œCâ€ dial will select the Aperture. The camera selects automatically the shutter speed.
In S mode (priority to shutter speed):
Rotating the â€œCâ€ dial will select the shutter speed. The camera selects automatically the aperture.
This is all explained in the SD14 user's manual, from page 37 to 41.
This works for Sigma AF lenses in manual focusing mode, but not for legacy lenses that doesn't have electronics and cannot communicate with the camera. In that case you have to force the aperture in the camera to 1.0, use Av mode and change the aperture manually on the legacy lens.
This is for the Sigma SD14, for the SD9 and SD10 and legacy lenses you have to set the aperture fixed to 5.6.
You have to keep in mind that M42 lenses are designed for a register of 45.46mm, and the register of sigma SA mount is 44mm. So make sure your adapter is 1mm thick (I do add some washer between my M42/PK adapter and the M42 lense).
I will probably try to use a Canon AFconfirm chip soon, as the communication protocol between lenses and body seems to be the same...
Sounds like your basing your opnions on a few poor quality M42 lenses? Good quality M42 lenses are easily the equal of modern Sigma equivalents, if there are any. For example, my old M42 mount Sigmatel 135mm f1.8 is excellent at f4-f5.6 but it has no modern Sigma equivalent.
Here is a sample:
Of course there is...Sigma dont make any lenses faster than f1.4 but I have a 2" f1.0, a 55mm f1.2 and a 85mm f1.2...Impossible speeds to achieve with Sigma lenses.
And as for quality, I'll put my Canon FD 85mm f1.2 L up against the Sigma 85mm f1.4 EX anyday, and the Canon will beat it easily at any f-stop.
Here are some samples, all taken wide open at f1.2:
Or you can simply use Manual mode as I do. No Sigma DSLR can meter accurately through a manual focus lens so the best solution is to set the camera manually. Setting the camera to M, A, or P mode makes no difference to the exposure when using a manual focus lens but at least by using M mode and setting the aperture on the camera to the same aperture as your lens is set to you make sure that the aperture you actually used for each shot gets recorded in the EXIF data. And there is nothing more annoying at not being able to rembember what aperture you used for a shot when someone asks you what aperture you used. Using A and setting it to f1.0 simply means that the the aperture used is always recorded as f1.0 in the EXIF data!
I'm wondering if anyone has ever tried the Canon AF confirm chips with the SD cameras? The protocols are the same, there have been SD cams converted to EOS mount. Supposedly everything but Image Stabilization worked.
So if the spacing and dimensions of the chip are compatible, perhaps it will be helpful. Either that, or find someone to make a split prism focusing screen. (It was a lifesaver on my 40D with manual lenses.)
It wont work because the Canon EF electrical contact block is different to the SA contact block...It would need a mechanical redesign to make the AF confirm chip fit the SA mount and given the low sales volumes of Sigma cameras it would'nt be economically viable to put such a chip into production.
I don't think SD cameras need an AF confirm chip: When focus is achieved, the green led in the viewfinder light up. But, for that to work, you need to first mount a SA auto lens each time you remove the batterie.
The problem with EF contacts block and SA contacts block is that the inner diameter of EF mount is larger than those of SA mount.
However, I heard some people did adapt Canon 50mm EF on SA mount and kept the automatism. Then I guess it should be tried, maybe first with a broken canon lens?
On the other way, I do have a stigmometer split focusing screen on my SD14 (imported from China at a very low cost - 19â‚¬) The focusing screen is not perfect, and I do have to adjust very precisely the screen.