lets just clarify a little, I've been there
Originally posted by richard64 Huh? With K and M lenses the mount on ther lens is metal, so all the contacts will be shorted. IIRC this is how the body detects that the lens is K or M rather than an A or later. Si IMO shorting the A and Data pins will do nothing because they are already shorted
no not all contacts touch the mount, the one that tells the camera that the lens is automatic apature (3rd from the locking pin) is recessed on the camera body, the pin must stick out from the lens
Quote: Perhaps you are thinking about
this modification? Mark Roberts actually
insulates part of the mount so that the camera can determine the maximum and minimum aperture.
this does not work, because the DSLRs disable matrix metering if the lens is out of auto apature mode I think mark roberts also states this only works on film bodies
Quote:
P-TTL means that the camera sends test flashes, and meters, then it adjusts the flash accordingly, do you see this with your modification?
When you say you get matrix metering, are you saying that you can set the camera to the matrix metering setting?
if it is working, but you need the lens in auto mode to do this, meaning that you have to also short the third pin from the lens locking pin, and that causes all sorts of other problems. Specifically the camera now thinks it has an A lens, and tries to figure out the metering based on the other contacts, and gets it wrong. Also, when you short the A poin, the apature activation lever operates to the extent necessary to set the F stop on an A lens, which is not the same as a manual apature (Non A) lens
Quote:
If you have to use the smallest aperture then it means that the flash is using full power. This means that there is no metering from the body, so P-TTL is not working. If you could use any aperture (and you can change the flash power for the on-board flash using the menu) then it would mean that P-TTL is working.
Richard
All of these work arounds in my opinion are a waste of time. I did an experiment where I actually converted a lens to A from K mount, by marking the apatures according to the Mark Roberts instructions
AND adding the pin for Automatic apature. Did it work, sort of, but exposure is all over the map. Why? Because the apature activation lever on a non A lens controls the apature differently. Most Non A lenses have the apature change diameter linearly with motion of this lever, where A lenses have the area change linearly with this lever. As a result the converted Non A lens got the exposure wrong at every setting varrying from -1.5 stops at max apature to +2 stops at min apature. In other words, it was almost useless.
If you are serious about flash work with non A lenses, as I said earlier, you have at this point 2 options, get an *istD (or DS but on the DS the internal flash isnot TTL capable) or get an AF540 FGZ and use it in the Auto mode.