Lens "hacking" ?s

[rbiemer]

I got an adaptor so I can use my Pentacon 6 mount lenses on my Canon Rebel--mainly the 500mm/f5.6 mirror lens I bought from Arax for my Kiev 60.
Nicely made but no electronics. Every thing mounts fine and focus seems to fine as well.
I intend to set the camera to "manual" and set shutter speed according to my meter(the lens is a fixed 5.6 aperture).
The questions about metering and camera settings:
Should I trust the in camera meter or use a handheld meter? I was playing with this set up this afternoon and was getting some seemingly odd readings using the cameras meter--it was sunny 16 weather but the camera was telling me that "correct" exposure was 1/8th at 5.6.😕
Any one else done something similarly silly? And have some helpful advice?
Thanks!
Rob

 

[RML]

Rob, how about doing both? Shoot a shot with the in-camera meter's recommendations, and the same shot with the hand meter's recommendations.

 

[Bryce]

Sounds like the camera is expecting the lens to stop down from the iris's setting when it metered.
Maybe there's a setting in a menu for using preset lenses?
I have Pentax SLR gear, and that's how I have to deal with older lenses on my digital body.

 

[jamiewakeham]

You need to set the camera to aperture priority and f/1.0 and to meter with the lens set at the correct aperture - this is how I used pentacon-6 and M42 lenses on my old EOS and it exposed slides perfectly. Essentially, when the camera cannot detect an electronically-linked EF lens it still tries to meter but doesn't know how far the lens will stop down from its current setting. Setting it to f/1.0 tells it that the lens won't stop down at all. There's no way to get full aperture metering.

Jamie

 

[rbiemer]

Jamie,
Thanks! I did that and I'm getting expusre readings that make much better sense!
Rob

 

[rbiemer]

I was out for a bit this afternoon shooting some local waterfalls--actually small details down stream as there isn't much water running now.
Some observations.
The 500mm /f5.6 on 35mm film is 750 or 800mm depending on how one computes the "crop factor" and so has a very small field of view.
I shot based on Jamie's suggestion about using the EOS body and got seemingly reasonable shutter speeds. And I used a handheld meter and set sppeds according to that. Between the two methods, I should have some OK photos.
DOF is exteremelyshallow with this lens; parts of an inch at 15 or 20 feet.
I don't have my tripod right now--it may be in Italy with my dad(he borrowed it but I'm not sure if he took it with him or not) so I borrowed one that is not as solid as mine. When I get the roll back, I'll know how well my time was spent.
I think I got some interesting shots of rocks and water--not too much motion blur of the water; speeds were mostly 1/90th to 1/180th with a few in shadier areas of the stream 1/30th. When I get my tripod back, I'll be shooting through either an orange or ND 2 filter to hopefully run the exposure times out some.
And lastly about today's shooting:
A paunchy, middle aged guy with a camera and a honking big a$$ lens will make every young sunbather around very uncomfortable.😱
But I wasn't trying to be stealththy in any way and asked one of the closer kids if she'd like to see what I was shooting. With her friend hovering close by, she looked through the VF and uttered a few fatal words: "Pretty neat, I guess. Too bad my mom's not here she's into this old fashioned stuff too!"
After which, they all ignored me.
Rob

 

[jamiewakeham]

Glad to have been of help, Rob. You should find that you get identical readings with handheld and reflected metering now.

<pedant>
A little confusion that I ought to clear up, though; the lens is still acting as a 500mm lens in 35mm format. It'll have exactly the same FoV as a 500mm lens that was built for the EOS. The optical characteristics, including how far away from the lens its focal point it, haven't changed. The difference is that lenses of the same focal length have different FoVs on different formats. An 80mm lens is standard on 6x6 but a short telephoto on 35mm.

So the correct statement would be that a 500mm lens has the same FoV on 35mm as a 700-800mm lens on 6x6.
</pedant>

Anyway, do get the 180m Sonnar for your Kiev and EOS. It's a wonderful lens on either format!

Cheers
Jamie

 

[rbiemer]

Jamie,
The hand held meter and the in camera meter were pretty close, but those do have very different FOVs 😀 and so read different amounts of the scene in front of me.They did agree in some of the shadier areas of the stream bed I was shooting in.
As for the FOV of the lens, I apparently have been influenced by the digi slrs and how the lens equivalents are expressed.
Still: a very small FOV.
Thanks!
Rob