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Thread: Olympus 43 glass can cover bigger frame

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    Olympus 43 glass can cover bigger frame

    Lloyd Chambers (digllloyd) in his tests says Olympus glass cannot cover a frame bigger than 4/3 image circle. There were some rumors Olympus would build a larger than 4/3 frame camera (E7?)

    diglloyd.com/blog/2012/20121019_1-Olympus-SHG-coverage.html

    I would like to know how Mr Chambers mounted the 14-35 Zuiko on his D800 and where do those baffles (rectangular shades limiting the image circle) come from.

    I built a simple camera obscura (box , tape, sheet of paper), set the Zuiko to the same parameters (25mm, infinity focus) and took some pictures of the image projected on my paper screen (under a blanket).

    No baffles. The image circle I got is ca 32 mm. Enough to cover the APS-C frame.
    I did not measure how the diameter changes with the focal length.
    Last edited by nugat; 9th February 2014 at 07:38.

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    Re: Olympus 43 glass can cover bigger frame

    There are various parameters to determine or define the image circle. The most extreme is physical vignetting, but quite often the practical limitation kicks in earlier (at a lower image height) and is determined by MTF (how much contrast does the lens render at a given frequency).
    Quite often the image circle increases with closer focus and is usually larger with longer focal lengths within a set a lenses.
    So it might be possible to use 43-lenses with an APS-C-sized sensor but not with every lens, at all apertures and at infinity and especially not when seeking a high IQ in outer image zones.

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    Senior Member Riley's Avatar
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    Re: Olympus 43 glass can cover bigger frame

    I grabbed this photo years ago from someone using an Olympus 43 kit lens mounted (as best as could be) on a Pentax 1.5x sensor camera. The lens had to be pre-focussed on a 43 body, and the aperture is of course wide open.

    Jay Turberville once tried an assortment of 43 lenses doing something like what nugat is doing. He found the 50/2 to have an image circle closer to 40mm



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    Re: Olympus 43 glass can cover bigger frame

    Quote Originally Posted by nugat View Post
    where do those baffles (rectangular shades limiting the image circle) come from.
    What that digllloyd "blogger" did not do is - he did not bother to show what is inside the lens from its rear end... actually here it is... hopefully that answer your question (and then there is something that can be removed )


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    Re: Olympus 43 glass can cover bigger frame

    How do you get to see those baffles on a lens that is not mounted on the camera?
    I cannot see anything like that from the back when freeholding the lens and they do not project onto my camera-obscura paper screen. My lens is bought new in 2010, #180004265
    Effectively I get the image circle 32mm at 25mm/infinity. Whereas diglloyd measures (how?) 23mm diameter at f-length 35mm with the baffles projecting.
    I also measured now the image circle dia. at 14mm and 35 mm f-lengths.
    It is ca 28mm at the former and ca 30mm at the latter. So it seems that the 25mm f-length offers the biggest diameter of the light patch.
    It seems that this particular 4/3 lens (Zuiko SHG 14-35mm) can cover the canon APS-C (26,7mm dia ) and with some difficulty at the wider end other manufacturers' sensors (28.2-28.4mm dia). Of course the question is what happens with MTFs once the distance from the center exceeds 21.6mm (43 standard).




    Quote Originally Posted by deejjjaaaa View Post
    What that digllloyd "blogger" did not do is - he did not bother to show what is inside the lens from its rear end... actually here it is... hopefully that answer your question (and then there is something that can be removed )


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    Senior Member Riley's Avatar
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    Re: Olympus 43 glass can cover bigger frame

    another post has been made after he checked
    diglloyd.com blog - Olympus SHG 14-35mm f/2 ED ? Does It ?Cover? more than a Four Thirds/MFT Sensor? (Updated, Camera Obscura)
    he suggests it still wont cover APSC at 28.2 mm (which is 1.5x)

    the item Ive been pushing for years now is a larger 43rds,
    the so called Super 43rds which is a 20x15mm sensor for 300sq mm on 25mm diagonal. This is within the patent draft.
    This would of course mean all our lenses would be a little wider, 7mm would become 10.6mm EFL instead of 14mm
    and with an EV of 1.526 ever so slightly better DoF control, or a half stop

    also this would differentiate SLRs from micro,
    without a point of difference there is no reason for 43rds to exist.

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    Re: Olympus 43 glass can cover bigger frame

    Quote Originally Posted by Riley View Post
    he suggests it still wont cover APSC at 28.2 mm (which is 1.5x)
    which is not 1.5x only... Canon APS-C is 1.6x... Sigma APS-C (pre SD1) is 1.7x... hence mythical m43/43 APS-C sensor could be less than 1.5x and still be APS-C.

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    Re: Olympus 43 glass can cover bigger frame

    Quote Originally Posted by nugat View Post
    I cannot see anything like that from the back when freeholding the lens and they do not project onto my camera-obscura paper screen. My lens is bought new in 2010, #180004265
    and the photo is of 2008 lens

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    Senior Member Riley's Avatar
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    Re: Olympus 43 glass can cover bigger frame

    Quote Originally Posted by deejjjaaaa View Post
    which is not 1.5x only... Canon APS-C is 1.6x... Sigma APS-C (pre SD1) is 1.7x... hence mythical m43/43 APS-C sensor could be less than 1.5x and still be APS-C.
    indeed
    Canon APSC 26.68mm, 327 sq mm 3x2
    Sigma APSC 24.8783mm, 285 sq mm 3x2
    S43 25mm, 300 sq mm 4x3

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    Re: Olympus 43 glass can cover bigger frame

    I'll quote parts of my last post from 43rumors:
    "...
    What Sony/Olympus could do is to pick up the standard Sony APS-C sensor 23,5 x 15.6 mm (diagonal/image circle diameter 28.2mm). Establish the new format (“FTmax”?) image circle at somewhere 26mm. Note that Canon’s APS-C image circle is 26.2mm. Within that image circle three “native”* ratios could be achieved: 4:3, 3:2 and 16:9. The last one especially attractive to film makers. Having a true super35mm frame on the FTmax would be a unique sellinig point to the film crowd.
    That way the E7 could be a nice APS-C/FTmax/super35 camera utilizing the existing Zuiko SHG glass. The interesting part is how the MTFs would change from the current 10.8mm limiting distance from the image field center.
    Adding another 2.2 mm each way of the diagonal might see some deterioration, but given the currently near-perfect MTF, the performance could be still better than that from any APS-C system.
    As a side note for the filmamkers I once compared the performance of the Zuiko 14-35 with that of a pro film glass (Angenieux Optimo ) on the panasonic Af100. Olympus won.
    *”native” that is not cropped from one 4:3 ratio sensor. The same way the oversized sensor of Panasonic GH2 can deliver three frames of the same diagonal but different ratios..."


    Good Mr Chambers checked his first findings and used the camera obscura method. His diameters are within the error range (+/- 1mm) either of us could have made.
    I still don't know how he mounted his Zuiko on D800 and where did he get the baffles' shadow from---the first time. Note that in his camera obscura pics the baffles are gone too.

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    Senior Member Riley's Avatar
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    Re: Olympus 43 glass can cover bigger frame

    Super35 is highly desirable, thanks for reminding me

    tell me, what we are looking at is wide open, but as we close the aperture what happens then? Is it possible that closing down a half stop would put us back in the same positions (edges and corners) as with regular 43rds?

    Also, with increased sensor height the MTF would ordinarily increase

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    Re: Olympus 43 glass can cover bigger frame

    Quote Originally Posted by Riley View Post
    Super35 is highly desirable, thanks for reminding me

    tell me, what we are looking at is wide open, but as we close the aperture what happens then? Is it possible that closing down a half stop would put us back in the same positions (edges and corners) as with regular 43rds?

    Also, with increased sensor height the MTF would ordinarily increase
    I checked what happens with the image circle on my 35 mm summilux-M as the aperture closes. Basically the size stays the same, except the narrow circular band of light fall-off , sharpens up in the middle. The boundaries of the image circle become more defined, somwhere in the middle of this twilight circle.
    I don't have any manual 43 lenses to check for that format.
    I would think that stopping down normally increases the image circle.

  13. #13
    Senior Member Riley's Avatar
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    Re: Olympus 43 glass can cover bigger frame

    I think it infeasible that a lens would be designed with no tolerance at its image circle edges, and that within reason, stopping it down would resolve whatever issues there were.

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    Re: Olympus 43 glass can cover bigger frame

    Quote Originally Posted by nugat View Post
    I would think that stopping down normally increases the image circle.
    Not in the case of 4/3rds lenses, especially because of the telecentricity touted by Olympus.

    Either they (4/3rds lenses) are telecentric and therefore will not cover more area when stopped down or they cover more than the Olympus 4/3rds area and are not telecentric.

    One can not have both.

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    Re: Olympus 43 glass can cover bigger frame

    Haven't experimented with m4/3 lenses, but I can tell you that various DX Nikkors throw wildly different image circles. Some zooms I've tried will cover a full FX sensor at some focal lengths and others don't even come close. I bet the m4/3 lenses are all over the place on this as well.

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    Re: Olympus 43 glass can cover bigger frame

    Quote Originally Posted by Vivek View Post
    Not in the case of 4/3rds lenses, especially because of the telecentricity touted by Olympus.

    Either they (4/3rds lenses) are telecentric and therefore will not cover more area when stopped down or they cover more than the Olympus 4/3rds area and are not telecentric.

    One can not have both.
    except that "telecentric" does not mean exactly 90 degrees... it pretty much might be simply absence of the extreme angles as was not an issue w/ film cameras.

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    Re: Olympus 43 glass can cover bigger frame

    nugat wrote:

    What Sony/Olympus could do is to pick up the standard Sony APS-C sensor 23,5 x 15.6 mm (diagonal/image circle diameter 28.2mm). Establish the new format (“FTmax”?) image circle at somewhere 26mm. Note that Canon’s APS-C image circle is 26.2mm. Within that image circle three “native”* ratios could be achieved: 4:3, 3:2 and 16:9.
    A brilliant idea, really; especially the 'native' ratios (including 1:1).

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    Senior Member Riley's Avatar
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    Re: Olympus 43 glass can cover bigger frame

    even with a diagonal of 26mm,
    thats a sensor 20.8 x 15.6, 324.48 sqmm in 4x3 terms
    virtually 1 to 1 with Canon APSC

    hopefully Sony wont languish on a decision and get it rolling

    juts tried placing 43 lenses over my 5D mount to see what I would get

    Zuiko 7-14 at 7mm

    Zuiko 7-14 at 14mm


    Zuiko 11-22


    Zuiko 9-18
    Last edited by Riley; 22nd October 2012 at 21:00.

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    Re: Olympus 43 glass can cover bigger frame

    Riley, guys,
    These are not any baffles inside the lens that project the weird rectangular shape onto the image circle.
    This is the lens hood (shade).
    Take off the plastic to see the full image circle projected by the Zuiko.
    That was what diglloyd had on during his first test too.
    The shade limits the lit area severely, especially at the wide end.


    Quote Originally Posted by Riley View Post
    even with a diagonal of 26mm,
    thats a sensor 20.8 x 15.6, 324.48 sqmm in 4x3 terms
    virtually 1 to 1 with Canon APSC

    hopefully Sony wont languish on a decision and get it rolling

    juts tried placing 43 lenses over my 5D mount to see what I would get

    Zuiko 7-14 at 7mm

    Zuiko 7-14 at 14mm


    Zuiko 11-22


    Zuiko 9-18

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    Senior Member Riley's Avatar
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    Re: Olympus 43 glass can cover bigger frame

    7-14/4 SHG shade is integral, not removable from the lens
    but zooming is such that even at 8mm the frame size is very large, beyond APSC

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    E7 design

    The final design of E7 could be like this:

    --E5 like body with additional dedicated dials for AF and exposure modes.
    --universal lens mount enabling the use of m43, 43 and film PL lenses
    --multiaspect Sony APS-C sensor ( 24-36 mpix), "oversized" for Super43*
    --native image circle diameter 26mm (like Canon APS-c) for true ratios of 3:2, Super4:3*, 16:9 (Super35 mm)
    --possibly the Sony SLT technology and EVF
    --dual contrast/phase AF detection
    --XQD 2.0 flash cards enabling DNG raw HD (2k) and 4k film recording (1000 Mbytes/sec, >2 terabyte) at 60p
    --Pro audio/battery grip with XLR connections and audio levels

    *Super43 is trademark by Riley

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    Re: Olympus 43 glass can cover bigger frame

    Quote Originally Posted by deejjjaaaa View Post
    except that "telecentric" does not mean exactly 90 degrees... it pretty much might be simply absence of the extreme angles as was not an issue w/ film cameras.
    Quite right. Olympus were always careful with their wording. They described the (4/3) lenses as "nearly Telecentric".

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