[LRflex] Re: Summicron 50mm take apart?
- From: Keith Edwards <keith.r.edwards@xxxxxxxxxxx>
- To: leicareflex@xxxxxxxxxxxxx
- Date: Sat, 01 Aug 2009 21:38:49 +0100
Hi Richard/ Aram,
Richard I can 'second' your note below and add a little - I have a 400D
(same as US Rebel series) and with a Leica 80/ 1.4 attached I find it
best to stop the lens down to f2.8 to focus - below f4 AF Confirm is not
reliable in less than bright conditions, wide open the depth of field is
often so thin that its difficult to get focus right. Exposure around
this f stop is also generally reliable. Low light performance with the
AF confirm is a bit hit and miss (sometimes its hard to get any light to
light) but with my eyesight limitations better than my attempts to
manually focus (even on the film cameras).
Best regards
Keith
Richard Ward wrote:
Hi Aram,
Cool suggestion on that Nikon Eye Piece. I'll check it out. I
wanted to pass along a 'theory' about something you said in your post.
re: "I could not use my manual focus lenses on my Rebel with out it.
Even with the focus confirmation adapter. I am not always able to get
those focus spots to light up. Perhaps too dark." Quite Likely your
observation is 'right on' about things being too dark for your Rebel
to achieve focus comfirmation. The Rebel series don't have the
'latest/greatest' AF systems in them - they aren't uber efficient in
general, are lacking in low light sensitivity, and as the apertures
get smaller or the light gets dim their weaknesses pop up like a
jack-in-the-box shouting Hi-Hello-Look At Me! (Pardon the humourous
anthropomorphication!). I have 'less' of an issue using a 20D, but
it's systems are dated, too when compared to a 40/50D and roundly
whooped by the 1D wonder machines. (I pray each day for the camera
faeries to slip any 1D under this peasants tattered pillow!).
My 'theory' in regard to your post is to ask whether you're
attempting to focus confirm with your rebel's sensor when you've
already 'stopped' the lens down? At even f4 but especially down past
f5.6 the Rebel sensors are into territory where they weren't
'engineered' to work well in. They certainly 'can' achieve results and
depending on the volume of light in your scene coming in the lens and
the subject you're attempting to focus upon they're able perform
surprisingly well. I work around the issue by using the 'Pre-AF'
techniques of Focusing Then Stopping Down, Pre-Focusing for a specific
spot I 'want' the action to be framed at, and manipulating Depth of
Field when possible to cover up focusing errors. Trust Me! those
beautifully engraved Distance Markings and Depth of Field Scales on
the 'old' manual focus lenses are Uber Handy! and can really save a
photographer's bacon in tough situations.
Also! you might want to experiment with your rebel's af system and
get a feel for what it does and doesn't like to focus on 'in general'
and experiment at what light levels the AF system starts geting flaky
on you. I did it just by spending time playing with my camera
regularly in my home in the evening. The lower light levels get tricky
and homes have lots of low contrast stuff to challenge af sensors. By
getting a feel for what my camera likes and doesn't like doing, I can
take that experience with me out into the field.
Richard
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