75 Summilux Quandary

[rjsphd]

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I bought a 75mm summilux a while back and, have not used it much.  At infinity it is well focused at all apertures, but at closer distances I am having a devil of a time getting much depth of field, even at f4 or 5.6.  Seems to me there are 3 likely answers: 1) my incompetence at focusing with my m240, 2) its the nature of the beast-- the lens is just built with a narrow DoF, or 3) my lens needs some work on it.

 

Assuming 1 isn't the issue I would welcome some wisdom on the following:

 

A) Does this lens really have a paper thin DoF (like 6 inches at f5.6)?

Is the 75mm summicron's DoF deeper?

C) Is it likely a Leica CLA would help and, if so, what does it cost? (I tried calling Leica but they have been no help.)

 

Thanks in advance.

[pico]

I bought a 75mm summilux a while back and, have not used it much.  At infinity it is well focused at all apertures, but at closer distances I am having a devil of a time getting much depth of field, even at f4 or 5.6.  Seems to me there are 3 likely answers: 1) my incompetence at focusing with my m240, 2) its the nature of the beast-- the lens is just built with a narrow DoF, or 3) my lens needs some work on it. [...]

 

Thorsten Overgaard has the good Leica specs on his site here. Scroll down for the depth-of-field in Meters.

 

Indeed, it has shallow DOF, however the very same DOF as the slower 75mm lenses when at the same F-stops. It's a matter of physics.

[IWC Doppel]

I think from memory it has a shallower depth of field than the Noctilux at f1 when wide open

 

Probably worth testing with a ruler or similar at 45 degrees

[TheGodParticle/Hari]

I bought a 75mm summilux a while back and, have not used it much. At infinity it is well focused at all apertures, but at closer distances I am having a devil of a time getting much depth of field, even at f4 or 5.6. Seems to me there are 3 likely answers:

 

1) my incompetence at focusing with my m240

 

2) its the nature of the beast-- the lens is just built with a narrow DoF

 

3) my lens needs some work on it

 

 

Assuming 1 isn't the issue I would welcome some wisdom on the following:

 

A) Does this lens really have a paper thin DoF (like 6 inches at f5.6)?

Is the 75mm summicron's DoF deeper?

C) Is it likely a Leica CLA would help and, if so, what does it cost? (I tried calling Leica but they have been no help.)

 

Thanks in advance.

1) my incompetence at focusing with my m240

 

-> if you have an m240, why don't you cross check the focus with Live View?

 

 

2) its the nature of the beast-- the lens is just built with a narrow DoF

 

-> no, physics still applies

 

 

3) my lens needs some work on it

 

-> maybe, but could also be your body that's out of spec. Do other lenses focus accurate on the body?

 

 

C) Is it likely a Leica CLA would help and, if so, what does it cost? (I tried calling Leica but they have been no help.)

 

-> can't answer till we don't know if something is wrong with your lens. If something is indeed amiss, the cost will depend on what the problem is (cost of spare part or adjustment + man hours spent on repair) Send it in to Wetzlar or to some reputed technician around you.

 

When was the last time it was serviced?

[otto.f]

3C

[IWC Doppel]

A CLA and code from Leica in the UK will be circa £300 or so, nearer £125 from a specialist

[TheGodParticle/Hari]

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A CLA and code from Leica in the UK will be circa £300 or so, nearer £125 from a specialist

Assuming there is nothing wrong with the focus mount which can increase the cost rather quickly

[pgk]

The 75mm Summilux does have a paper thin depth of field - wide-open. Otherwise it behaves virtually identically to both 75mm Summicron and Summarit at the same apertures wrt dof.

 

I have a copy which was adjusted and coded by Leica and is now spot-on and I have no problems with it. In the right conditions it focusses accurately (and I wear varifocals). If you are having problems its either that the lens needs to be adjusted (worth the cost even if high because a poorly focussing lens is useless except with live-view), you are trying to operate it in adverse conditions or your eyesight/diopter/glasses need to be sorted out for RF focussing. (It could also be the camera which is in need of RF adjustment but if you have other lenses working fine this is unlikely).

 

Amongst the many Leica RF myths are suggestions that 'difficult' lenses cannot be accurately focussed - they can, but require that they are correctly adjusted, that they are used in appropriate conditions of light and contrast to focus in (not low contrast, low light), and that you are able to see a clear, in-focus view of the RF patch in the viewfinder. If any of these are not adequate then focus will be difficult and hit & miss.

 

The 75mm Summilux is a fabulous lens and getting harder to get hold of so you are fortunate and its well worth persevering with your lens.

[rjsphd]

Thank you all.  I am going to bite the bullet and send it in to Leica for a CLA and coding.   Fingers crossed it ain't a big problem.

[otto.f]

They will probably ask you to send your body with it (no pun intended)

[NB23]

They will probably ask you to send your body with it (no pun intended)

Why? Calibrating a lens is done by a standard. No need to match bodies to lenses, which usually results as a mess.

 

The body, if it needs calibration, will have to be calibrated to the standard, regardless of the lens.

[otto.f]

Just my experience

[Jeff S]

Why? Calibrating a lens is done by a standard. No need to match bodies to lenses, which usually results as a mess.

 

The body, if it needs calibration, will have to be calibrated to the standard, regardless of the lens.

 

Leica NJ routinely asks customers to do this, despite separate camera/lens calibration, because they want to minimize need to re-send items, avoid any chance of user misinformation and to identify any other issues. In fact, they often ask the user to send in their camera and multiple lenses.  (They told me this after I asked them why they do it, given independent camera/lens tests).

 

LV on the M240 can at least better help identify a focus mis-calibration to start.

 

Jeff

[NB23]

They do it to calibrate the camera to standard specs. But certainly not to match it to the lenses.

[lct]

Leica NJ routinely asks customers to do this, despite separate camera/lens calibration, because they want to minimize need to re-send items, avoid any chance of user misinformation and to identify any other issues. In fact, they often ask the user to send in their camera and multiple lenses.  (They told me this after I asked them why they do it, given independent camera/lens tests). [...]

 

Same here but on demand or by default, Leica calibrates cameras and lenses to standard specs which has never posed any problem for me.

[Sully]

RJSPHD,

 

Sending your Summilux and camera in for calibration will give you a perfect excuse to buy an SL.  Focusing with the SL is so good that I began using my Noctilux and 75 Summilux again without any reservations.  The magnification focus aid of the SL is so fast and easy even in low light, I found that auto-focus lenses were not needed under regular shooting situations.  With a Nikon or Canon DSLR there is no magnification possibility, so, you really do need auto-focus to get good results.  Even using just the regular EVF (without focus magnification) focusing accurately is really very good with the SL.  The sad thing about using the SL is I don't pick up my M240 that much.

 

Ciao,  Sully

[adan]

I've tried multiple copies of the 75 Summilux on the M9. A definite pattern emerges that those upgraded with six-bit coding also had more consistent focusing. No doubt simply that Leica bench-tests the adjustment after replacing the lens mount.

____________________

 

As to 75mm (and other) DoF - physics is all very well in an ideal world. In the real world, there are significant other factors. Below are two crops from shots I made when transitioning from the 75 f/1.4 to the 75 f/2 recently (weight issue, not imaging).

 

Just for grins.

 

Due to the effects of spherical aberrations ("Leica Glow"), the Summilux (left or top, stronger color fringing) actually has more practical DoF (wider "field" of legible lettering and numbers) than the Summicron-APO. At a wider aperture (1.4 vs. 2.0) and identical focus distance/magnification.

 

There is a huge difference in "drawing," which effects DoF.

 

Especially when comparing older lens designs and newer ones, I'd strongly recommend actual experience with the lenses in question. An ounce of experimental evidence is worth a gigatonne of theory.

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[Jeff S]

They do it to calibrate the camera to standard specs. But certainly not to match it to the lenses.

 

What part of my statements 'despite separate camera/lens calibration' and 'independent camera/lens tests' wasn't clear?

 

Jeff

[pgk]

Due to the effects of spherical aberrations ("Leica Glow"), the Summilux (left or top, stronger color fringing) actually has more practical DoF (wider "field" of legible lettering and numbers) than the Summicron-APO. At a wider aperture (1.4 vs. 2.0) and identical focus distance/magnification.

 

There is a huge difference in "drawing," which effects DoF.

 

Especially when comparing older lens designs and newer ones, I'd strongly recommend actual experience with the lenses in question. An ounce of experimental evidence is worth a gigatonne of theory.

 

The Apo lens looks as though it is producing an image illustrating that it is an Apo design, whereas the non-app, older lens seems to have a greater spread of focus which gives the 'appearance' of a larger area being sharper. You make an interesting point though because although the older lens gives the 'appearance' of greater depth of field it also lacks the clarity of the newer design.

 

I'm pretty sure that Zeiss published some information on the way depth of field can be varied by design parameters so its not absolutely identical for all lenses but for most purposes its not far off.

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Hallo,

Look here: Leica M

[NB23]

What part of my statements 'despite separate camera/lens calibration' and 'independent camera/lens tests' wasn't clear?

 

Jeff

You may find it clear but I don't.