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Why is the M4/3 mount so big
- Thread starter Wellington100
- Start date
Well if you didn't know what telecentric is how could you ask the original question in the first place?
For instance we know that Sony's 24mm eq. had bad edges. Leica M digital had problems at the edges too, until it used microlenses on its sensors.
Even, because of short distance to flange Leica M and CV lenses are rumored to have poorish edges on µ4/3.
With such short registers some lenses especially wides have very steep incident angles over the sensor at the edges and that ruins resolution, if I understand it well.
That Sony can obviate the problem without making big lenses that wreck the performance/size ethos of mirrorless is yet to be seen.
You can only go that far with in-camera correction, and some would prefer to have none, like in the new PL 25mm.
So, yes, an amount of telecentricity might have been preserved for the better lenses.
Sammy, I believe, has the opposite problem: a longer distance to flange which is borderline for accepting the Leica register.
As explained in many posts m4/3 is a compromise, but a v. good one
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Photostream: http://www.flickr.com/photos/amalric
Fredrik Glckner
Senior Member
On the Panasonic Lumix G 8mm f/3.5 fisheye lens, the front element fills the lens completely:
http://m43photo.blogspot.com/2010/11/lumix-g-8mm-f35-fisheye.html
I'm not sure the lens mount could be made so much smaller. The M4/3 lenses are pretty telecentric, and the electrical contacts are between the rear lens element and the lens mount.
Perhaps it could have been made smaller if the electrical contacts were inside the lens mount ring. But that would have been more unstable mechanically, perhaps.
If the communication between the lens and camera is digital, I don't understand why so many electronical contacts are needed. Why is it not enough with, say, three-four of them?
http://m43photo.blogspot.com/2010/11/lumix-g-8mm-f35-fisheye.html
I'm not sure the lens mount could be made so much smaller. The M4/3 lenses are pretty telecentric, and the electrical contacts are between the rear lens element and the lens mount.
Perhaps it could have been made smaller if the electrical contacts were inside the lens mount ring. But that would have been more unstable mechanically, perhaps.
If the communication between the lens and camera is digital, I don't understand why so many electronical contacts are needed. Why is it not enough with, say, three-four of them?
Wyepics_Wizard
Well-known member
If you look at the 35mm SLR's, the mount diameter seems to be a little bit bigger with each new "system". The Nikon as the oldest is 44mm, pretty much the diagonal size of the frame, whereas the Pentax, Minolta Alpha and Canon EF are progressively newer and larger.
I once saw a picture of a Nikon S3 next to a mock up of the Leica S2 both with the lenses off and the Nikon looked like a pinhole camera in comparison with the S2's mount.I's something like 80mm diameter which is a lot, especially as the frame diagonal is not really that much greater than a 35mm frame
I once saw a picture of a Nikon S3 next to a mock up of the Leica S2 both with the lenses off and the Nikon looked like a pinhole camera in comparison with the S2's mount.I's something like 80mm diameter which is a lot, especially as the frame diagonal is not really that much greater than a 35mm frame
Antonio Rojilla
Senior Member
Mike Fewster
Forum Pro
Great answer Almaric.
I think the jury is still out on this class of camera. mft/Nex try to give a full range of lenses on smallbodies with slr viewfinder characteristics. This creates problems re the balance of overall body size and lens size. Some of the problems can be fixed with a RF approach rather than a slr appoach. RF of course has limitations of its own.
The whole thing about "ugly" cameras and the flack thrown at the nex is interesting (let's face it, there is minimal difference between Nex and mft proportions as far as the average public is concerned.) We may just need to get used to seeing cameras ina new way. ie, a lens that we hold and balance the gear with and a small package on the back that packs most of the controls. Are we just all tied to preconceptions about what a camer should look like and in fact the game has moved on.?
Mike Fewster
Adelaide Australia
I think the jury is still out on this class of camera. mft/Nex try to give a full range of lenses on smallbodies with slr viewfinder characteristics. This creates problems re the balance of overall body size and lens size. Some of the problems can be fixed with a RF approach rather than a slr appoach. RF of course has limitations of its own.
The whole thing about "ugly" cameras and the flack thrown at the nex is interesting (let's face it, there is minimal difference between Nex and mft proportions as far as the average public is concerned.) We may just need to get used to seeing cameras ina new way. ie, a lens that we hold and balance the gear with and a small package on the back that packs most of the controls. Are we just all tied to preconceptions about what a camer should look like and in fact the game has moved on.?
--I think that the reasons Roy and Erik gave you are the good ones.
As an example the lens next to the 17mm, is the smallest one could adapt to M4/3, the Industar 69, a Tessar triplet from the Russian Chaika half frame camera. Of course it has no motor, no AF.
The Tessar triplet Could be the simplest devised: 4 lenses in 3 groups. Works with the M39 mount, which is smaller than m4/3.
However I also have the old 9-18 which has a huge front element, or an old 135/2.8 weighing 500 gr. The mount can still take it but I am carefult to hold the kit by the lens. Some have mounted bigger lenses, but one must be careful of the structural integrity of the mount, possibly with SHG zuiko lenses. Larger diameter helps to better distribute the weight.
So it's a matter of compromises. Some lenses can be small and still have big front elements, like some Leicas and CV, but I suppose that the exit lens will still be relatively small since it is so close to the film/sensor plane.
RF mounts like Leica, or half frame cameras' ones were smaller, but they accomodated only a limited range of lenses, not at the extremes of the focal range like a SLR had to do. It is interesting to see that the m4/3 mount is something in between the two.
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Photostream: http://www.flickr.com/photos/amalric
Mike Fewster
Adelaide Australia
I'm sorry you must be joking. The readers here at dpreview, at least the ones that have/had 4/3 cameras must know it.
Please look it up at Olympus and Panasonic site.
Telecentricity has been one of the key factors in choosing the mount diameter on 4/3.
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Digifan
Wellington100
Forum Pro
Presumably if I had known what it was I would not have needed to ask the question.
Are you basically saying that the lenses have a bigger imaging area than the sensor? In much the same way that FF lenses do on DX cameras. That would be a reason that would make sense to me as the centre of the imaging area has better IQ than the edges?
Don't get me wrong I am not criticising the m4/3 system, I bought my son an EP1 and we have had great fun finding old Nikon and Pentax lenses for it and failing to find any C mount lenses, I am simply asked what I believe is a valid question about the size of the mount relative to the sensor and lens diameters, this is a gear forum and its a legitimate question. So far most answers (other than yours) have been somewhat speculative I think.
Oh, not at all. I think that yours is an interesting question that made me rethink a few others. One always assumes things like telecentricity are known, but the users' list keeps expanding so it's not a given.
The image circle ist still another matter. However it is interesting to see that lenses like the Industar 69 or C mount lenses vignette the least compared to other mirrorless.
I am not a technician at all, but my limited experience leads me to think that on various counts O&P choice was a fairly good one, in that it allows a v. good performance/size ratio.
Pen also recalls the Pen F film half frame experience. Those were excellent lenses which still work as a dream in Micro. If you find any you could then compare them to the present lenses, and see if they are very different, considering one has factor in micro-motors.
I guess much experience has been gathered there because engineers had to deal with half the size of 35mm, while providing a decent resolution. In fact it is still excellent with digital, by the reports I read.
Am.
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Photostream: http://www.flickr.com/photos/amalric
The image circle ist still another matter. However it is interesting to see that lenses like the Industar 69 or C mount lenses vignette the least compared to other mirrorless.
I am not a technician at all, but my limited experience leads me to think that on various counts O&P choice was a fairly good one, in that it allows a v. good performance/size ratio.
Pen also recalls the Pen F film half frame experience. Those were excellent lenses which still work as a dream in Micro. If you find any you could then compare them to the present lenses, and see if they are very different, considering one has factor in micro-motors.
I guess much experience has been gathered there because engineers had to deal with half the size of 35mm, while providing a decent resolution. In fact it is still excellent with digital, by the reports I read.
Am.
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Photostream: http://www.flickr.com/photos/amalric
E
Erik Magnuson
Guest
Most of them do. The image circle of a simple lens of 50mm focal length is (wait for it) 50mm. (Note: wide angle lenses are not simple lenses. They are typically reverse telephotos with extra elements at the back to spread the image circle out.) If you ever shot with large format (or used an enlarger), this would be a more natural concept to you because the imaging circle is a real issue you have to deal with in selecting lenses.
I started to include telecentricity in my post but decided to omit it for simplicity. Remember, I said "look at the back of lenses" and "take the most aggressive design"? Well, if you think about it, a perfectly telecentric lens will have a rear element diameter of at least the diagonal of the imaging area. Now add room for structure to hold the elements securely (and you can't let them poke inside the mount too far if you have a mirror) and you have your minimum mount diameter. If Olympus had not insisted in strong telecentricity for 4/3, the mount diameter could have been smaller.
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Erik
Antonio Rojilla
Senior Member
WTF???
I owned an E-1, I own a GH2. Yet I'm not a fanboy of any brand. I don't care about brands.
My question remains: source about the 'pretty telecentricity' of M4/3 lenes?
http://antonio.rojilla.com
I owned an E-1, I own a GH2. Yet I'm not a fanboy of any brand. I don't care about brands.
My question remains: source about the 'pretty telecentricity' of M4/3 lenes?
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http://antonio.rojilla.com
Wellington100
Forum Pro
I reread the definition on Wikipedia. Basically a telecentric lens creates an accurate 2D image of a 3D scene. 4/3 was developed to accommodate the bigger lenses and rear lens diameter needed to accomplish this.
In moving to micro 4/3, though, neither Panasonic nor Oly are claiming their lenses are telecentric anymore so they can be smaller and lighter but obviously the capacity of the mount to accommodate the bigger telecentric lenses remains.
That makes perfect sense to me. Oly have put some of the extra available real estate to good use with their collapsing lenses which still have room for the focus motor in them.
These lenses really do make the systems more compact.
Thanks for the info. It is much appreciated.
I'm a huuuuuge fan of these light weight collapsing designs. It makes all the difference in the world when I'm trying to stuff a lens into my front pocket.
I actually have both the non-collapsing panny kit lens & the collapsing Oly kit lens, and have spent a good solid day comparing them. Unless I'm planning on making use of filters, the collapsing Oly is the one I reach for. & I steal the thin rear cap from the Panny so it's extra slim. Panny didn't go after the collapsing design. But they did manage to cram in OID in a few of their lenses.
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'I have no responsibilities here whatsoever'
JonB1975
Forum Enthusiast
Just look at the difference in size between Nikon's and Canon's mounts.
Sticking with the same mount for decades has caused major development headaches for Nikon for years. It was probably the main reason they stuck with APS-C sized sensors for so long. It is a tribute to their engineers that when they finally bowed to market pressure and went full frame they produced such good cameras and lenses (& I am a Canon fan...). It has meant though that their recent designs are limited in how they use old lenses.
Canon on the other hand bit the bullet and introduced the EOS mount (back in 1987 - annoying their customer base) as the old FD mount was unable to accommodate AF. They made it much larger too, which I am sure has made some aspects of lens design easier for them. Witness the fact that Canon makes the 85mm & 50mm at f1.2 whereas Nikon's equivalent lenses only go to f1.4 - they are limited by the diameter of the bayonet mount.
Sorry to go on about Canon/Nikon, but I think this illustrates the point why the m4/3rds mount is comparatively large. I own a GF-1 and several lenses (all tiny!) and love it.
Sticking with the same mount for decades has caused major development headaches for Nikon for years. It was probably the main reason they stuck with APS-C sized sensors for so long. It is a tribute to their engineers that when they finally bowed to market pressure and went full frame they produced such good cameras and lenses (& I am a Canon fan...). It has meant though that their recent designs are limited in how they use old lenses.
Canon on the other hand bit the bullet and introduced the EOS mount (back in 1987 - annoying their customer base) as the old FD mount was unable to accommodate AF. They made it much larger too, which I am sure has made some aspects of lens design easier for them. Witness the fact that Canon makes the 85mm & 50mm at f1.2 whereas Nikon's equivalent lenses only go to f1.4 - they are limited by the diameter of the bayonet mount.
Sorry to go on about Canon/Nikon, but I think this illustrates the point why the m4/3rds mount is comparatively large. I own a GF-1 and several lenses (all tiny!) and love it.
E
Erik Magnuson
Guest
Nikon has made several 50-58mm f/1.2 lenses
http://www.mir.com.my/rb/photography/companies/nikon/nikkoresources/50mmnikkor/index3.htm
But 50mm f/1 and 85mm f/1.2 need the wider EOS mount diameter.
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Erik
twonker
Senior Member
JonB1975
Forum Enthusiast
I remember - but did they have any electronics in them? I think there wouldn't be enough space...
From http://www.four-thirds.org/en/microft/index.html 'Benefits of Micros Four Thirds':
"The new lens mount diameter is about 6 mm smaller than before because this size allows the mount to transmit the same optical flux to the Four Thirds System while still retaining the required strength."
So the MFT mount allows telecentric lenses by design and lenses can be large/heavy
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