Evidence for and against aperture control

is there a way to use good old NIKON AIS lens on 5d mark2? I hear there is adapter for nikon to EOS. will that be ok to use?

[ralph-FR]

is there a way to use good old NIKON AIS lens on 5d mark2?

If "AIS" is F mount compatible, yes you can. But even if you can mount it via the adapter, make sure the lens doesn't protrude too deep into the mirror box... I've read it can occur.

You can force the Aperture on Every EOS, just press the "depth of field preview button" (closing the aperture) and while you press the button disconnect the lens, tape the contacs and remount the lens.

Wowowww..... thanks for the great tip! I've heard of this trick before but forgot all about it. I always wished for aperture control on the 5D2 video so I can stop down the Sigmonster (to f/9 natively) when using TCs for better IQ, and to increase DOF with macro lenses. Whatever ISO and shutter speed the camera wishes to use after I fixed the Av is ok with me, as long as I can still apply EC.

When infinity focus is not important, a variation of this technique is to use a non-reporting 12 mm extension tube in lieu of the messy tape trick. Mount the lens to the 5D2, stop down to the desired Av, press DOF button and unmount the lens. Attach the unwired ET, remount the lens and you're ready to go!

Romy

[ralph-FR]

I always wished for aperture control on the 5D2 video so I can stop down the Sigmonster (to f/9 natively) when using TCs for better IQ, and to increase DOF with macro lenses.

If you ever get a demo camera again, please test that !! we still don't know if the camera will accept that trick...

If it does, there's better than a close-up tube :

IMG_3036.jpg (60.29 KiB) Viewed 4637 times

standard flat wires that you'd hook up to the pins, with a switch on the other end to short them, simulating the "unmount-tape-remount". Now I need to find a smaller one with less tracks (ideally only 2).

(Patent pending)

I always wished for aperture control on the 5D2 video so I can stop down the Sigmonster (to f/9 natively) when using TCs for better IQ, and to increase DOF with macro lenses.

If you ever get a demo camera again, please test that !! we still don't know if the camera will accept that trick...

If it does, there's better than a close-up tube :

IMG_3036.jpg

standard flat wires that you'd hook up to the pins, with a switch on the other end to short them, simulating the "unmount-tape-remount". Now I need to find a smaller one with less tracks (ideally only 2).

(Patent pending)

I see no reason why it shouldn't work...... manual stopping down of aperture of EOS lenses (as described in this DOF button method) has been a common practice when using unwired extension tubes for still macros. Likewise, metering is also TTL . I expect AF and IS not to work, but we won't be missing these anyway. Still, as you said, we need to test it with 5D2 to confirm everything.


Thanks for the photo of an alternative to ETs or taping..... it gave me an idea of another simple approach - just cut out some rectangular plastic sheets and insert one of these between the contacts during the unmount/mount procedure..... that should break the contact and simulate a taped approach, without the messy stickiness. Any cellophane bag thick enough to withstand the friction between the pins should be good enough.


Addendum - you can already simulate this with any EOS DSLR and lens. Set your desired Av, press (and hold) DOF preview button, start to unmount the lens just partially so contacts are broken but the lens is still physically attached to the body. The Av should read 00 - this confirms that the contacts are broken. The camera will now allow you to shoot and the aperture stays where you set it.

[ralph-FR]

I see no reason why it shouldn't work...... manual stopping down of aperture of EOS lenses has been a common practice

Because we'll do it in movie mode... and movie mode on the 5D seems VEEEEEEERY special and crippled. What if they forbid non-EOS lenses (say, if the camera WANTS to have aperture control since you can't)

insert one of these between the contacts during the unmount/mount procedure.....

The whole point of my solution is to avoid unmounting/remounting (dust, wear, waste of time) everytime you want to change aperture... and perhaps I could do that while filming... even if I fear the camera will just stop the capture if it detects a lens being unmounted (Live View stops as soon as the lens goes missing)

contacts are broken but the lens is still physically attached to the body.

And suddenly, the lens unmounts when you weren't paying attention, and crashes before your feet... not fun !

I see no reason why it shouldn't work...... manual stopping down of aperture of EOS lenses has been a common practice

Because we'll do it in movie mode... and movie mode on the 5D seems VEEEEEEERY special and crippled. What if they forbid non-EOS lenses (say, if the camera WANTS to have aperture control since you can't)

insert one of these between the contacts during the unmount/mount procedure.....

The whole point of my solution is to avoid unmounting/remounting (dust, wear, waste of time) everytime you want to change aperture... and perhaps I could do that while filming... even if I fear the camera will just stop the capture if it detects a lens being unmounted (Live View stops as soon as the lens goes missing)

contacts are broken but the lens is still physically attached to the body.

And suddenly, the lens unmounts when you weren't paying attention, and crashes before your feet... not fun !

Just tested the procedure on the 40D + 100-400 IS..... live view works even when the Av is "00". Things are looking better! I agree that your wired method is very convenient when you need to change Av quickly during filming.

[ralph-FR]

live view works even when the Av is "00". Things are looking better!

No, since we still don't know if movie mode will be possible without a lens (Live View works, but we now know they are very different)

Your trick will be much more simple and efficient than mine, if you're brave enough to drill a second hole for the locking pin on each of your lenses, so that you can shoot with the lens twisted and still have it safely locked in place. I'll still opt for the non-destructive flat wire trick !
Now all I need is the EOS mount pinout diagram, to see if the pins can be shorted or if it's harmful for the camera (if I happen to short the pins that bring current to the lens).
If they can't be shorted, I'll have to interpose the 2 wires between the leftmost pin and the corresponding contact.

Just tested the procedure on the 40D + 100-400 IS..... live view works even when the Av is "00". Things are looking better!

No, we still don't know if movie mode will be possible without a lens (Live View works, but we now know they are very different)

Your trick will be much more simple and efficient than mine, if you're brave enough to drill a second hole for the locking pin on each of your lenses, so that you can shoot with the lens twisted and still have it safely locked in place. I'll still opt for the non-destructive flat wire trick !

Yes, the only conclusive test to confirm that it works is filming with an actual 5D2.

Regarding the plastic sheet trick, no need to drill a new hole for the locking pin. Just insert the sheet over the pins after unmounting (taking care not to block the rear optics), and remount till the locking pin engages again. It would be nice to have a small portion of the sheet sticking out of the lens barrel so one can press it against the barrel when mounting and minimize sheet movement. There is enough play between the contacts and mount surfaces to accommodate the thickness of the sheet, in the same manner as a tape can be physically placed.

I only suggested the partial unmounting procedure to quickly confirm that Av 00 will allow the camera to shoot, but certainly the locking pin must always be engaged during actual filming.

[ralph-FR]

Regarding the plastic sheet trick, no need to drill a new hole for the locking pin. Just insert the sheet over the pins after unmounting

But you are still unmounting the lens to insert some stuff inside the mount... I want to avoid the whole unmounting/fiddling with the plastic bit/remounting...

I only suggested the partial unmounting procedure to quickly confirm that Av 00 will allow the camera to shoot, but certainly the locking pin must always be engaged during actual filming.

Hence a second locking hole, to shoot safely with the lens partially twisted.