Tim Ashley M(240) Review

[tashley]

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Some points to consider...

 

The rangefinder can't have one offset for one lens and another offset for another lens; it only has one offset. It is nothing new, of course, to set the offset to the front if you have a lens with a lot of focus shift. You seem to be saying your rangefinder is tailoring the focus for different lenses; that is what the lens cams do, not the rangefinder.

 

If you have two lenses that disagree at the same distance with the same camera (should be clear what I mean), then one of the lenses is off--it's a matter of mathematical necessity. There is no way you can substitute a different rangefinder and have both lenses accurate.

 

It is already a stretch for a rangefinder to get the standard lens right (that is what the "bend" adjustment is for).

 

I am fully aware of that.

 

I think the key word here is 'seem' because I am not saying that at all. I am referring to the way that the system works, the system being the combination of lens and RF. I am assuming, and in this I might be wrong, that lenses which need front focussing within their thin, wide open DOF as I describe (in order to constrain the developing tendency to focus shift with stop down to remain within the deepening DOF) have a shape of cam that reflects this. But such a mechanical refinement is within extremely fine tolerances and the m8/9 rangefinder couldn't be reliably calibrated to 'pick it up' or if they could, would then tend to drift. The new RF seems to me to be better able to use this subtlety in the shape of the cam.

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[marknorton]

Continuing my theory that the reason the rangefinder is easier to use is because the sensor is thinner and fits more easily within a zone of good focus created by the lens.

 

Although not exact, the simple 1/u + 1/v = 1/f equation approximates the behaviour of the lens.

 

The Leica tables for the 50mm Summilux ASPH give the depth of field at f1.4 and 2 metres as 1.934 - 2.070 metres - a total of a little less than 14 cm.

 

Plug the values into the equation, and the zone behind the lens where a sensing element will see these sharp images is 51.238 to 51.327, about .089mm deep.

 

So, if the rangefinder is sufficiently accurate to place everything that matters in the sensing element within that zone, you will get a sharp image. Too far forwards or too far back or simply too big to fit in the space and you are in trouble.

 

1/10 mm is much more than the thickness of film emulsion which suggests all will be fine with film. My supposition is that the M8/M9 sensor effective depth may well have been a significant proportion of that "allowance". which made alignment all the more critical. If the new sensor is just 1/10 of the thickness (say), there is going to be much less sensitivity to critical alignment.

 

Trouble is, we do not know what these thicknesses are, the Kodak sensor specification gives no clue from what I can see.

[Peter Branch]

Continuing my theory that the reason the rangefinder is easier to use is because the sensor is thinner and fits more easily within a zone of good focus created by the lens.

 

Although not exact, the simple 1/u + 1/v = 1/f equation approximates the behaviour of the lens.

 

The Leica tables for the 50mm Summilux ASPH give the depth of field at f1.4 and 2 metres as 1.934 - 2.070 metres - a total of a little less than 14 cm.

 

Plug the values into the equation, and the zone behind the lens where a sensing element will see these sharp images is 51.238 to 51.327, about .089mm deep....

 

These figures seem to be derived from formulae using a 0.030 mm circle of confusion. At either end of the "Sharp Focusing Range" the light in the circle of confusion will actually be spread over some 19 pixels. The implication being that the image resulting from objects at these distances will be anything but sharp.

 

My so far limited experience with my M suggests that the RF has negligible backlash. It’s subtle but relative to other older bodies the effect is quite detectable albeit small.

[marknorton]

The figures are taken from Leica's own depth of field tables, just as an example. The less you are prepared to accept loss of sharpness at the limits, the great the requirement that the whole of what matters in the sensor is positioned criticially and centrally within those limits. It's clear though that if the sensor is thinner, there is additional wriggle room.

 

I've probably pursured this argument as far as I can. Without concrete information on the effective thickness of the sensor, inevitably it's a case of clutching at straws.

 

That said, my own experience now is that the M rangefinder is indeed easier to use than the beast I struggled with in my M9s over the last 3 weeks while travelling. That - to my mind - more than justifies the new camera.

[k-hawinkler]

Hi Mark,

 

Many thanks.

That's very encouraging and I am looking forward to get my M.

[120]

...I am assuming, and in this I might be wrong, that lenses which need front focussing within their thin, wide open DOF as I describe (in order to constrain the developing tendency to focus shift with stop down to remain within the deepening DOF) have a shape of cam that reflects this. But such a mechanical refinement is within extremely fine tolerances and the m8/9 rangefinder couldn't be reliably calibrated to 'pick it up' or if they could, would then tend to drift. The new RF seems to me to be better able to use this subtlety in the shape of the cam.

 

The article didn't mention cams, only "knowing" rangefinders, so I wouldn't have guessed. So the difference in the 240 rangefinder is it's more "reliably calibrated" and doesn't drift; is that a fair assessment? So (my guessing) you checked some focus-shifters and found them offset to the front, and checked some well-behaved lenses and found them not offset; and conclude the offset is taken care of by the cam. Again, this should be a straight forward question for the service department; it seems more constructive than just to guess about things. Thank you for the additional info.

[tashley]

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The article didn't mention cams, only "knowing" rangefinders, so I wouldn't have guessed. So the difference in the 240 rangefinder is it's more "reliably calibrated" and doesn't drift; is that a fair assessment? So (my guessing) you checked some focus-shifters and found them offset to the front, and checked some well-behaved lenses and found them not offset; and conclude the offset is taken care of by the cam. Again, this should be a straight forward question for the service department; it seems more constructive than just to guess about things. Thank you for the additional info.

 

I mentioned in the article, in passing and amongst a very great number of other observations, that I felt that the RF 'seems to have been redesigned'. Which in my opinion it does. Mention of cams has come into it in this thread, in which I have tried to explore the idea further with a number of people. I have also made it clear that I would say some more about it in the piece I was working on, now published, on the 35 Lux FLE on the M240.

 

If you are the sort of person, and you have every right to be, who insists on every observation being verified scientifically, then you are reading the wrong reviewer!

 

I write field reviews not lab reviews, I make observations which I back up where I can but I am perfectly comfortable with speculation as long as it is not ungrounded in my experience and as long as I make clear it is speculation. And there are some speculations which are unverifiable - without, in this case, taking the camera apart.

 

So with apologies I will carry on guessing where I think it might be useful and where I don't think a clear answer is yet available.

 

You might like to subscribe to Lloyd Chambers' excellent reviews - they would, I think, suit your needs more closely than my style, and he has just acquired an M240 for testing...

[k-hawinkler]

Hi Tim,

 

Thanks.

 

Tim Ashley Photography | Leica M 240 with 35mm F1.4 FLE - some observations

 

I read the article and don't think you need to invoke any particular RF focusing smarts.

If the light sensitive layer of the sensor is indeed sufficiently thin to fit well into the DOF of the 35 FLE lens, then it makes sense to have the lens adjusted so that a small residual amount of focus shift doesn't move it out of the DOF when stopping down.

 

I have the previous 35/1.4 lens that shows quite a bit of focus shift and Don Goldberg adjusted it perfectly for f/1.4.

It will be interesting to see how that lens behaves once I have my M240.

 

Thanks again for your article.

I don't think it should be very controversial if interpreted with some discretion/leeway.

[tashley]

Hi Tim,

 

Thanks.

 

Tim Ashley Photography | Leica M 240 with 35mm F1.4 FLE - some observations

 

 

Thanks again for your article.

I don't think it should be very controversial if interpreted with some discretion/leeway.

 

[120]

...

Plug the values into the equation, and the zone behind the lens where a sensing element will see these sharp images is 51.238 to 51.327, about .089mm deep.

 

...

 

For any particular lens it will not be a flat zone of sharpness, but more like a bowl or some such...and there was some account of this when making film gates.

[UliWer]

Thank you, Tim, for your examples with the 35mm Summilux asph. (FLE).

 

Tim Ashley Photography | Leica M 240 with 35mm F1.4 FLE - some observations

 

I studied them for quite a while now, and all I can say is that you should let Leica look at it. I don't know the lens, though from what I see something is very odd. If Leica would say that they thought the lens o.k., I'd say it is not worth the money. Sharpness - at least fully opened - doesn't seem to me sufficient at all. Even if there might besome misfocussing on the first example, the others can't be explained alike. My pre-FLE - notwithstanding the focus-shift it shows - seems to be much better. I had guessed an old pre-asph lens if you hadn't told, but even then one would not exspect the odd shaped zones of in-focus/out-of-focus in your outside examples.

[tashley]

Thank you, Tim, for your examples with the 35mm Summilux asph. (FLE).

 

Tim Ashley Photography | Leica M 240 with 35mm F1.4 FLE - some observations

 

I studied them for quite a while now, and all I can say is that you should let Leica look at it. I don't know the lens, though from what I see something is very odd. If Leica would say that they thought the lens o.k., I'd say it is not worth the money. Sharpness - at least fully opened - doesn't seem to me sufficient at all. Even if there might besome misfocussing on the first example, the others can't be explained alike. My pre-FLE - notwithstanding the focus-shift it shows - seems to be much better. I had guessed an old pre-asph lens if you hadn't told, but even then one would not exspect the odd shaped zones of in-focus/out-of-focus in your outside examples.

 

Interestingly this was a replacement - the first one I had was so badly adjusted that it went straight back. But the MTF graphs do suggest some quite serious field effects and other reviewers have found similar things - but the lens is clearly showing very slightly better on centre detail than the RX-1, which is very very highly rated at DXO...

 

Quite a few lenses seem to have more notable field curvature effects than they are known for when you look as them closely and this one is known for it anyway.

 

As I say in my piece, I think that this shows up more on a higher resolution sensor. I am very curious to hear from other people with the same lens and camera though!

 

Edit: the example at f5.6 with the urns outside is a scene I often shoot to determine field effects and the performance of the 35 lux FLE here is not unusual... The review I did of the Nikon 28mm f1.8g showed very similar results (it's a very sharp lens but also tricky) but so do a lot of fast wides... The Famous Zeiss 21mm f2.8, which i also reviewed, does something very similar.

[Guest]

The figures are taken from Leica's own depth of field tables, just as an example. The less you are prepared to accept loss of sharpness at the limits, the great the requirement that the whole of what matters in the sensor is positioned criticially and centrally within those limits. It's clear though that if the sensor is thinner, there is additional wriggle room.

 

I've probably pursured this argument as far as I can. Without concrete information on the effective thickness of the sensor, inevitably it's a case of clutching at straws.

 

That said, my own experience now is that the M rangefinder is indeed easier to use than the beast I struggled with in my M9s over the last 3 weeks while travelling. That - to my mind - more than justifies the new camera.

 

If I understood that correctly, guys howling a 0.95 around with the aim to have the thinnest possible DOF are better served by an M9 than an M240?

 

How does this go with many old statements here from the pre-240 era, that film is more "forgiving" to focus errors by being thicker than the sensor? I read you saying, that the thinner M240 sensor is more forgiving (and hence a reason to buy it) than the one in the M9. Sorry for being a bit thick myself.

[mjh]

How does this go with many old statements here from the pre-240 era, that film is more "forgiving" to focus errors by being thicker than the sensor?

There is no way you could usefully compare the thickness of film with the thickness of a sensor, at least as far as sharpness is concerned. For film there is a relatively simple relationship between the thickness of the emulsion and maximum sharpness. With a sensor, thickness and sharpness aren’t directly related.

[Photoskeptic]

You might like to subscribe to Lloyd Chambers' excellent reviews - they would, I think, suit your needs more closely than my style, and he has just acquired an M240 for testing...

 

Hmm, probably not, Tim. Lloyd doesn't have much nice to say about the M.

[tashley]

Hmm, probably not, Tim. Lloyd doesn't have much nice to say about the M.

 

That, in a round about way, was my point :D:D

[120]

That, in a round about way, was my point :D:D

 

I've had the new camera on order since the get-go, and was not criticizing it

[tashley]

I've had the new camera on order since the get-go, and was not criticizing it

 

I didn't think you were, not at all. And I hope that yours arrives soon and that you love it!

 

EDIT: though I do appreciate the implication of my three grins - I think I meant that in exchange for the kind of extreme rigour you want in a review (and actually I think I am only a small margin less rigorous, but then reviewing isn't my day job) you'd probably end up with a more dystopic view of the camera.

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Hallo,

Look here: Leica M

[jonoslack]

Hmm, probably not, Tim. Lloyd doesn't have much nice to say about the M.

 

Hi There John

Just a word about Tim - perhaps you don't know him as well as I do!

He is different from Lloyd in a number of ways - three which spring to mind are that he doesn't charge, he has a sense of humour and he writes well.

 

But don't imagine for a second that he is less rigorous - he might not fill his blog with a stream of boring comparisons, but you can be pretty certain that he's making those comparisons.

 

I don't always agree with him - but that's only because I'm lackadaisical and careless.

 

all the best

[Photoskeptic]

Hi Jono, I've been following Tim's posts since the first M8 burst upon the scene (you too, for that matter). You are correct in that I don't know Tim at all, only through his posts - seems a decent chap. His opinions, however, mean a great deal to me and he has earned my admiration through his determination to find and test and use the best camera gear most of us can afford and I comment frequently on his blog. I don't have much respect for Lloyd Chambers due to his shooting off his mouth with opinions before he has even held certain cameras, ie Leica M and spewing vitriol from a foul mouth in a public rant about others. Even though I subscribe to his tests, I took a certain pleasure in crossing him off my "favorites" list.

Regards,

John