Leica S lens image circles

[bradleygibson]

It struck me as curious that the Leica's new S system considers the 70mm lens the normal lens, when the S2's sensor has a 58mm diagonal.

Does anyone know if the S lenses actually have a 70mm image circle, perhaps sufficient to cover 645 (56x42mm) (or since Leica likes 3:2, 58x28mm or 56x37mm, if sensor manufacture is limited to 645 sizes)

Even looking at the MTF graphs Leica published it seems they're easily able to substitue a new value on the X-axis, the way they're written...

Overactive imagination?  Or has Leica left themselves some room for expansion for later generations of the S family?

[BJL]

It struck me as curious that the Leica's new S system considers the 70mm lens the normal lens, when the S2's sensor has a 58mm diagonal.

In 24x36mm format (35mm), the image diagonal is about 43mm, and 50mm is considered a "normal lens". It is rare that the normal lens for a system actually equals the frame diagonal; usually it is longer. For example, 645 (56x42mm) has a 70mm diagonal, but "normal" lenses are often 75mm or 80mm.

Still, 70mm for 30x45mm format is the "narrowest" normal I know of, matching 58mm in 24x36mm format.

... has Leica left themselves some room for expansion for later generations of the S family?

I doubt it: Kodak could easily provide a somewhat larger sensor right now (it makes a 49x37 with the sme 6 micron pixels), and price is no barrier for the Leica S2 it seems, so why would Leica cripple its first model by imposing a "crop" on the new lens system? The S2 needs to succeed in winning over some MF users from alternative like 44x33mm and 48x36mm at similar or lower prices, so I doubt that Leica has the luxury of hobbling the S2 in order to sell a larger sensor upgrade in the next model.

[EricWHiss]

It struck me as curious that the Leica's new S system considers the 70mm lens the normal lens, when the S2's sensor has a 58mm diagonal.

Does anyone know if the S lenses actually have a 70mm image circle, perhaps sufficient to cover 645 (56x42mm) (or since Leica likes 3:2, 58x28mm or 56x37mm, if sensor manufacture is limited to 645 sizes)

Even looking at the MTF graphs Leica published it seems they're easily able to substitue a new value on the X-axis, the way they're written...

Overactive imagination?  Or has Leica left themselves some room for expansion for later generations of the S family?

Hi Brad,
Last year around the announcement of the S2,  I did read something to the effect that the camera system was designed with potential upgrades in the future. Of course this could mean two possible things - higher pixel count or larger footprint.  Both cases  would  probably mean an entirely new camera body as Leica did with the M8 to M9.  
Eric

[michael]

It's in the video interview with lens designer Peter Karbe that i just posted.

Michael

[ErikKaffehr]

Hi!

While your are waiting for that video, you may check this: http://www.imx.nl/photo/leica/leica/page154/page154.html

Sorry! Its up already, no sleep tonight!

Great video, BTW!

Best regards
Erik

It's in the video interview with lens designer Peter Karbe that i just posted.

Michael

[jackmacd]

Michael,
Of all your wonderful videos from Leica, the video of Karbe was most welcome.
I felt that I was in the room with you and Peter, and the information was most encouraging to someone who has this system on order, praying that I am making a smart decision. Put out a video on how to best use this system for landscapes and I will be a buyer. But of course, you need to amortize you video costs across hundreds of buyers, and I'm not sure such a video will be as smart a business move for you as a workshop would be. This will be my first move to DMF so I do not have your challenge of worrying about your legacy lens commitments that you have.  Good to hear these lenses will work well for the S3 and S4. This from a former Pentax 6x7 shooter, so you can see the appeal to me of the S2 form.
Thanks,
Jack

[bradleygibson]

It's in the video interview with lens designer Peter Karbe that i just posted.

Michael

Unfortunately the iPhone (my only computing device at the moment) is Flash impaired, and even still, I might not get a chance to listen to Peter until the weekend.  But I'll definitely be listening to the whole thing.

If you or anyone can post the short version
of the answer here, I'd appreciate it.

Thanks, (and especially for the interview, Michael--this is great stuff!)

[tho_mas]

If you or anyone can post the short version
of the answer here, I'd appreciate it.

in short: the S2 lenses are designed for the sensor size of the S2. But, according to P. Karbe, they outresolve the current pixel pitch so they are designed for future sensors as well (sensors with same size, but smaller pixel pitch).

[Christopher]

in short: the S2 lenses are designed for the sensor size of the S2. But, according to P. Karbe, they outresolve the current pixel pitch so they are designed for future sensors as well (sensors with same size, but smaller pixel pitch).

If true wrong move. I find it hard to believe that Leica really was dump enough to just design the S2 lenses for their current camera. But hey it's Leica.

[tho_mas]

If true

watch the video at TC 04'20''

[pcunite]

If true wrong move. I find it hard to believe that Leica really was dump enough to just design the S2 lenses for their current camera. But hey it's Leica.

I am not sure. I don't want to look back at this post 5 years from now and feel embarrassed... but 40mp outta be enough for most things. Yes being able to crop out an eye-ball and make an 8x10 print out of it is neat... but how many need to do that? More megapixels than you need means waiting for the computer to finish it's work. How large are homes these days? That dictates the size of prints. What is the largest monitor these days? I mean 30" is just huge!

I think that 40mp is the sweet spot for cropping and post processing for common sized prints and viewing. Instead of improving the number of pixels that it can create I would like to see improvements in all other areas of imaging.

[bradleygibson]

Thank you, thomas.

Like Christopher, I too had hoped for a different answer.  The cost premium for creating larger sensors will continue to diminish into the future.  I had hoped the lenses were actually designed with this in mind.  It is hardFor me to see how an S3 or S4 will compete noise and DR-wise with a 56 x 42mm Phase One P90+...  I'm a bit surprised they'd give themselves this kind of competitive disadvantage.

Well I look forward to hearing Peter in his own words soon.

Best,

[narikin]

he clearly states "no larger" for the image circle.
and "there is no space for more" which might mean in the body, or in the image circle... I think he meant the body has no space for a bigger sensor.

a little worrying for me is the fact that he says a major consideration was the leaf shutter, which explains the not-so-impressive speed, bulk and size of these lenses.
"the size is set by the central shutter" - so even in non CS lenses, which I suspect will be by far the bigger seller, we have a lens designed around a shutter that is not present, and is consequently restricted in its max Aperture + bigger + heavier than it needs be, for maybe 10% of users?

interesting to know he rates the new generation Phase/Mamiya 80mm D lens highly too - it is an excellent lens, and resolves P65+ sensor requirements.

thanks for the interview, Michael.

[narikin]

Bigger image circle and bigger sensor need bigger mirror, then the camera body will be thicker.
Xin

good point.
I'd imagine they can squeeze 1 or 2 mm around, while keeping existing sensor-lens 'thickness', but thats it.

[bradleygibson]

Bigger image circle and bigger sensor need bigger mirror, then the camera body will be thicker.

Xin

True, until the shutter becomes electronic.

[pcunite]

a little worrying for me is the fact that he says a major consideration was the leaf shutter, which explains the not-so-impressive speed, bulk and size of these lenses. "the size is set by the central shutter" - so even in non CS lenses, which I suspect will be by far the bigger seller, we have a lens designed around a shutter that is not present, and is consequently restricted in its max Aperture + bigger + heavier than it needs be, for maybe 10% of users?

More than 10% of users want faster sync speeds... more like 90%. But yeah... you have the cheaper lenses that are not really cheaper for them to make most likely... mostly the same cost for both I would imagine.

[BJL]

in short: the S2 lenses are designed for the sensor size of the S2. But, according to P. Karbe, they outresolve the current pixel pitch so they are designed for future sensors as well (sensors with same size, but smaller pixel pitch).

Which is the only sane way to do it for a high end system: choose a format size for a particular system once and for all, and design everything to work optimally for that format:
- lens mount dimensions that allow just enough room for the mirror box, rather than having extra depth for the larger mirror of a future larger format, which would restrict lens designs to have rear elements further from the sensor, hampering optical design optimization (retro-focal design needed more often and more severely with wide angle lenses).
- lenses, wide to normal in particular, optimized over the needed image circle, rather than constraining designs to cover larger image circles, which for example forces wides to have a wider angular FOV that the current format requires, leading to larger lenses and/or optically worse performance within the current image circle requirement.
- lens focal lengths that provide desirable field of view choices with the chosen format. Covering a future format size increase means either focal lengths that will be a bit shorter than ideal with the future larger format, or focal lengths that are a bit too long/narrow for the current format. [Here Leica S should have an immediate advantage over alternatives like 44x33mm sensors used with 645 lenses.]

I can see some argument for Leica choosing a larger format right from the start, but the argument for starting out with the dreaded "sensor crop" imposed on the bodies and lenses is bizarre: isn't that exactly what people complained about with the M8, and the 1.5x and 1.6x crop formats used with 35mm format lens mounts and lenses? To repeat larger sensors are available right now at a cost that is reasonable relative to S2 pricing, so that argument of waiting till prices come down to upsize the sensor makes little sense in this case.


P. S. The idea that 30x45mm is too small to be successful in the long run is also a bit strange; does anyone still believe that Canon and Nikon are doomed by being so tied to the even "tinier" 24x36mm as their largest format? Does anyone still believe that sensor costs at a given size are going to come down so much in the future that all serious photographers will shift from 4/3, EF-S and DX to 35mm, from 35mm to "intermediate digital medium formats" like 30x45mm, 33x44mm and 36x48mm, and from those intermediate formats to "full medium format" of 42x56mm (645)? Maybe some people still even believe that the future belongs to an Hy6 with 56x56mm sensor!

The main tasks for Leica to establish a niche for the S system are achieving and maintaining some cost/size/weight advantage over larger formats, and an IQ advantage over smaller formats.

[Misirlou]

Which is the only sane way to do it for a high end system: choose a format size for a particular system once and for all, and design everything to work optimally for that format:
- lens mount dimensions that allow just enough room for the mirror box, rather than having extra depth for the larger mirror of a future larger format, which would restrict lens designs to have rear elements further from the sensor, hampering optical design optimization (retro-focal design needed more often and more severely with wide angle lenses).
- lenses, wide to normal in particular, optimized over the needed image circle, rather than constraining designs to cover larger image circles, which for example forces wides to have a wider angular FOV that the current format requires, leading to larger lenses and/or optically worse performance within the current image circle requirement.
- lens focal lengths that provide desirable field of view choices with the chosen format. Covering a future format size increase means either focal lengths that will be a bit shorter than ideal with the future larger format, or focal lengths that are a bit too long/narrow for the current format. [Here Leica S should have an immediate advantage over alternatives like 44x33mm sensors used with 645 lenses.]

I can see some argument for Leica choosing a larger format right from the start, but the argument for starting out with the dreaded "sensor crop" imposed on the bodies and lenses is bizarre: isn't that exactly what people complained about with the M8, and the 1.5x and 1.6x crop formats used with 35mm format lens mounts and lenses? To repeat larger sensors are available right now at a cost that is reasonable relative to S2 pricing, so that argument of waiting till prices come down to upsize the sensor makes little sense in this case.


P. S. The idea that 30x45mm is too small to be successful in the long run is also a bit strange; does anyone still believe that Canon and Nikon are doomed by being so tied to the even "tinier" 24x36mm as their largest format? Does anyone still believe that sensor costs at a given size are going to come down so much in the future that all serious photographers will shift from 4/3, EF-S and DX to 35mm, from 35mm to "intermediate digital medium formats" like 30x45mm, 33x44mm and 36x48mm, and from those intermediate formats to "full medium format" of 42x56mm (645)? Maybe some people still even believe that the future belongs to an Hy6 with 56x56mm sensor!

The main tasks for Leica to establish a niche for the S system are achieving and maintaining some cost/size/weight advantage over larger formats, and an IQ advantage over smaller formats.

I agree completely, but I'd still like to see an offshoot of the S2. Same image circle size, but in a square format. Square mirror, square sensor, everything.

I'd also be happy with a camera based on the standard image circle of 35mm cameras, only in a square format.

I know, I know; it's completely ridiculous and won't ever happen.

[Christopher]

Well the downside is that we know for sure, that for S2 lenses we will always need a S2 camera or a smaller sensor camera. There will never be the chance for a full 645 to use these lenses :-(

[madmanchan]

My interpretation of Peter's comments is that the image circle size is fixed and is not subject to change. The comment regarding "room to grow" had to do with setting the optical performance bar so high in the current set of S series lenses, specifically targeting close to 80% MTF at 40 lp/mm (frankly, astounding), so that future sensors of the same total physical dimensions, but with smaller pixels (e.g., 5 microns or 4 microns, instead of 6 microns) would be able to take advantage of the lenses.