Back focus: 50/1.4 Summilux-M & 90/2 Summicron-M pre-asphs

[F456]

I have a Summilux-M 50/1.4 & 90/2 Summicron-M, both being the final non-aspherical versions. They focus fine on M6 & M7.

Should I expect any backfocus from them when stopping down on an M8? I know that the Apo-ASPH 90/2 and Elmarit-M 90/2.8 have no back focus at any aperture (Sean Reid), but he hasn't reviewed my two lenses.

And on a related topic, how likely would it be that M8s bought new last summer (2007) would need focus adjustment? Haven't detected any trouble with wider lenses - but obviously longer fast lenses would be more critical and I got terrible results recently with the 90/2 except at longer distances and heavily stopped down.

Thanks for anyone's experiences with these two lenses.
Tom

 

[Ben Z]

Hi Tom. I have those lenses too (except my 50 is the older 43mm-filter type and only therefore focuses to 1m). Both of them focus perfectly on my M8, which was bought last summer. The only lens I own which focused on my film bodies but not the M8 (images didn't quite line up at infinity) was my 50 Summicron (the focus-tab type). A call to DAG informed me to grab an allen wrench and adjust the rangefinder at infinity for that lens and that probably I wouldn't see the rest of my lenses then "go out". DAG was as always right.

 

[awilder]

I've owned the 50/1.4 pre-asph Summilux (both E43 and E46) and a 90/2 (E55) in the past. Neither the E43 Summilux or the 90//2 had any focus issues with film under the most critical testing criterion. The E46 Summilux focused past infinity and needed to be stopped down a bit to be sharp. If your 90 does not line up exactly at infinity focus on the M8 but does so in the M6 or M7, try adjusting the cam roller screw on the M8. If it lines up perfectly in all bodies but the M8 is still soft by f/2.8, send the lens and M8 to a good service person like Sherry Krauter or DAG to adjust as needed. Warning: DAG is very backed up with work at this time and turnaround may be slow.

 

[F456]

Thank you, Ben Z and awilder. I don't know if there's an equivalent to DAG in Britain, though; I know that when the M8 was introduced Leica at Milton Keynes were only working on film M-bodies and sending the M8s back to Solms.

I'm going to buy a 1.25x viewfinder magnifier first: it is quite certain my 52 year old eyes are not as hot as my 35 year old ones were when I first started focusing in poor light with Leica lenses at full aperture!

Tom

PS (vaguely relevant) How are people getting on with focusing and framing compact 135mm lenses?! Wondering whether to buy an Apo 135/3.4 again!

 

[F456]

Old 50/1.4 & 90/2 traded in!

Old 50/1.4 & 90/2 traded in!

Thought I'd let you all know the upshot of this thread. Couldn't get the 90/2 to behave at all on the M8 (and it's not easy on the eyes, getting exact focus,I have to admit), though it's been very accurate to focus on the film bodies. Makes me realize why it probably is very hard for ANYONE to get really clear focus, let alone composition, on a non-goggled 135mm.

A chance visit to Richard Caplan in London saw me come away minus the pre-ASPH 50/1.4 and 90/2 , traded in towards the new 50/1.4 Summilux ASPH.

It's fantastic, and - best of all - no focus shift at all that I can detect. Very happy with it, but a lot of money the poorer even after the double p/x. This is a wonderful lens that so far I've only used on the M8, where the long standard effect is nice for M-style photography. 51mm X 1.33 = 68mm, like the 70 end of a 35-70 zoom. Anyway, not too long to focus in a hurry.

I did like the old lenses on film though - just a different effect.

Shelled out for the v/f 1.25x magnifier as well. It's made a difference - or at least makes me feel more confident with rapid focusing. It takes just a couple of minutes to remember that the eyepiece stands off a little from the viewfinder. You don't bump your face on it more than once - this is a little accessory that's worth having, and I managed to get mine second hand (one and a half hand, if you go by the price - new they are around £200).

Tom

 

[JWW]

I have both lenses and there's no focus shift stopping down. Back focus at wide open can happen to any lens/body combo depending on how the rangefinder or lenses are set up. I had to adjust the M8 for my 75mm lux for focus using the allen wrench (easy-like idle adjust on a carb). All my other lenses work fine with this adjustment since the 75lux has the least tolerance for adjustment.

Jan

 

[Benjamin Marks]

I'd like to echo Jan's comment. I had a batch of lenses that worked great with my M8 under all circumstances right out of the box (50/1, 50/1.4 Asph, 50/2 tabbed 'cron, 35 Asph, 75/1.4, 75/2 and 90/2.8), some of which are very demanding lenses in terms of wide-open focus. Then I had another group of lenses that I just couldn't get to play nice. When wide open, some focussed in front of the indicated point, some focussed behind (50/1.5 Sonnar, 50/1.5 Summarit, 50/2 Hexanon, 50/2 rigid 'cron, 50/1.5 Canon in LTM, 43/1.9 Pentax in LTM, 90 Apo Ash, 135/2.8). I have had most of the lenses in the second group modified by DAG to correct their focus. My conclusion has been that the tolerances set at the factory for lenses to be used with film are too loose for use with digital. I used to think that a 50 was a 50 was a 50 . . . but then I got two 50's that just never agreed.

Then there are some lenses (like my 40/1.4 from CV), whose point of focus changes with respect to DOF as they are stopped down. These, you just have to learn to use within their limitations as the shift in focus is not a result of lens-mount tolerances, but rather inherent in the optical choices made by the lens designers. In these lenses, focus (which can be accurate wide-open) shifts slightly behind the indicated plane of focus for apertures between f:2.0 and f:8. By f:8, the depth of focus of the aperture has covered the effect and it is no longer an issue. Actually, I suspect that my 50/1.5 C-Sonnar exhibits this behavior but it is currently being tweaked again and then we'll see.

Ben Marks

 

[F456]

Ben and Jan,

Thanks for the replies. My set-up now is just as I want it: no focus errors at full aperture (except through occasional user error) and really just one lens that is known for a backfocusing shift as you stop down ( 35/1.4 Summilux ASPH), but in practice it has been excellent. Jan, I did get rid of the pre-A 50/1.4: it was a shame but I like its replacement even more - in fact, a lot more. For some reason I always preferred the 35mm out of the old Summiluxes.

Ben, I'd be very interested to know how you get on with the C-Sonnar when it gets back to you. Roger Hicks loves the effect of that lens, and I like the idea that its design bucks current trends.

Tom