Auto-aperture-stop-down?

[IkarusJohn]

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Sean Reid makes a lot of the fact that the SL does not provide for auto aperture stop down for R lenses (it has been mentioned here as well).  What this means is that with SLR cameras you always focus with an open aperture, and as you fire the shutter, a lever stops the lens down just before the shutter opens. Not necessary for the M rangefinder, as you don't need the aperture open to focus properly.  Most SLRs had a preview lever next to the lens so you could see through the stopped down lens - I never really found it much use for previewing depth of field, I'd have to say.

 

For accurate focussing M lenses on the A7 and R lenses on the M(240), I also recall Tim Ashley recommending focussing wide open, then stopping down before exposing.

 

I've never really agreed that this is necessary when using an EVF, unless you are concerned with exact focus in difficult conditions.  The reason I say that is, first if you are stopping down on a trickier lens (a pre-asph 35 Summilux for example), stopping down from 1.4 to 2.8 will put you smack into focus shift territory; and, second the EVF auto-adjusts brightness so you don't get that horribly black-greyed effect the pre-view button used to give on a SLR camera.

 

On both the NEX-5n and the A7r, I didn't find focussing M lenses stopped down much of an issue, and it was entertaining seeing he depth of field widening as you stopped down (don't really know how accurate that was, but it was fun).

 

My interest is purely academic as, at the moment, I don't have any R lenses and M lenses don't stop down - that means you will focus wide open and stop down anyway if you're wanting focus accuracy.  I don't really see that as a problem.

[edwardkaraa]

I fully agree and that is my experience with the EVF of the M240. One can easily focus stopped down even at very small apertures. When in doubt, focus magnification is just one click away, or automatically brought out if set like that.

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[Likaleica]

I will happily stop down my M and R lenses until better SL lenses are available.  

[lct]

Focussing at full aperture is in no way mandatory in my experience and is indeed the best way to get trapped by focus shift. I focus my M lenses at real aperture up to f/8 on the X-E2 and i use focus magnification the same way and at almost the same speed as the focus patch of a rangefinder. I don't have to press a button with the left thumb of a big toe though ... I just click on the thumbwheel that's all.

[edwardkaraa]

Focussing at full aperture is in no way mandatory in my experience and is indeed the best way to get trapped by focus shift. I focus my M lenses at real aperture up to f/8 on the X-E2 and i use focus magnification the same way and at almost the same speed as the focus patch of a rangefinder. I don't have to press a button with the left thumb of a big toe though ... I just click on the thumbwheel that's all.

We seem to be in agreement recently, lct

[John Black]

I prefer to focus wide open and then stop down.  If the lens has known focus shift issues, I will recheck the focus via magnification.  Stopping down and then focusing usually comes with alot of noise in the EVF (indoors and outdoor night shots) and that noise can make discerning critical focus difficult.

[pico]

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I prefer to focus wide open and then stop down. If the lens has known focus shift issues, I will recheck the focus via magnification. Stopping down and then focusing usually comes with alot of noise in the EVF (indoors and outdoor night shots) and that noise can make discerning critical focus difficult.

That approach is way too time consuming for an experienced Leica user. The moment is gone.

[cpclee]

The importance of auto aperture stop down is a function of how speedy you want to achieve focus and how wide is the lens you are shooting.  On the M240 I have trouble achieving focus fast enough (say within half a second) with a lens 28mm or wider using the EVF.  This is made even harder if you want to focus while the lens is stopped down.

 

I can focus within about half a second with the rangefinder no problem.

 

 

 

Sean Reid makes a lot of the fact that the SL does not provide for auto aperture stop down for R lenses (it has been mentioned here as well).  What this means is that with SLR cameras you always focus with an open aperture, and as you fire the shutter, a lever stops the lens down just before the shutter opens. Not necessary for the M rangefinder, as you don't need the aperture open to focus properly.  Most SLRs had a preview lever next to the lens so you could see through the stopped down lens - I never really found it much use for previewing depth of field, I'd have to say.

 

For accurate focussing M lenses on the A7 and R lenses on the M(240), I also recall Tim Ashley recommending focussing wide open, then stopping down before exposing.

 

I've never really agreed that this is necessary when using an EVF, unless you are concerned with exact focus in difficult conditions.  The reason I say that is, first if you are stopping down on a trickier lens (a pre-asph 35 Summilux for example), stopping down from 1.4 to 2.8 will put you smack into focus shift territory; and, second the EVF auto-adjusts brightness so you don't get that horribly black-greyed effect the pre-view button used to give on a SLR camera.

 

On both the NEX-5n and the A7r, I didn't find focussing M lenses stopped down much of an issue, and it was entertaining seeing he depth of field widening as you stopped down (don't really know how accurate that was, but it was fun).

 

My interest is purely academic as, at the moment, I don't have any R lenses and M lenses don't stop down - that means you will focus wide open and stop down anyway if you're wanting focus accuracy.  I don't really see that as a problem.