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Ivan Lee
Joined: 03 Feb 2008 Posts: 230 Location: Rio de Janeiro - Brazil
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Posted: Sun Oct 31, 2010 12:47 am Post subject: Strange behavior with the 58mm f/1.2 Rokkor |
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Ivan Lee wrote:
hey fellow lens lovers...
something very strange with my 58mm MC Rokkor 1.2 is bothering me. At f/1.2 and f/2 apertures, the image is the same! and I am absoluttely sure that the aperture closes at f/2. I mean, the bokeh is identical...
And comparing with my other f/1.2 lens (MD Rokkor 50mm) the behavior is different.
I set my camera at 0 EV, pointed at a white blank surface and closed the aperture from 1.2 to f/2 and then f/2.8... (full stops)
With my 50mm MD Rokkor, I closed from 1.2 to f/2 and the meter showed -1 EV, from f/2 to f/2.8 (-2 EV) and from f/2.8 to f/4 (-3 EV)
This is how it should be... 1.2 --> 2 --> 2.8 (full stops)
Now with the 58mm MC Rokkor:
1.2 --> 2 ( -2/3)
2 --> 2.8 (-2 EV)
Now some samples with the MD Rokkor, the brightness should look the same because the exposure is the same (obvious)
f/1.2 - 1/200
f/2 - 1/100
f/2.8 - 1/50
Now with the MC 58mm Rokkor
f/1.2 - 1/200
f/2 - 1/100
f/2.8 - 1/50
Look how strange is that... with the 58mm Rokkor the f/1.2 and f/2 photos looks identical except that the f/2 photo is brighter...
wow, I´m confused...
All I can think is that the f/2 setting is not f/2 for real...is something like f/1.4... but the aperture closes at f/2!! look how uniform the MD 50mm lens performs...
any ideas?
thanks! _________________ Ivan Lee Barcellos - Director of Photography
www.planoconjunto.com.br
Sony A7s
Lumix GH3
Minolta MC: Minolta MC 24/2.8 - Minolta MD 28/2 - Minolta MC 35/1.8 - Minolta MC 35/2.8 - Minolta MD 50/1.2 - Minolta MD Macro 50/3.5 - Minolta MD 100/2.5
Konica AR: Hexanon 28/3.5 - Hexanon 50/1.7 - Hexanon 57/1.4
M42: Industar 50-2 - CZ Pancolar 50/1.8
Olympus OM: Zuiko Auto-Macro 50/3.5 - Vivitar 28/2 Close Focus |
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francotirador
Joined: 17 Sep 2009 Posts: 894
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Posted: Sun Oct 31, 2010 4:31 am Post subject: |
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francotirador wrote:
I promise I'll give it a try with mine. But for me there is little difference in the bokeh _________________ Canon 5D II-Sony nex 6
Canon L 80-200 f 2.8 - Canon L 135 f2 - Canon FD 135/2.5 convert to EOS - Yashica 50 1.4 ML - Canon FD 50 1.2 - Distagon 35mm 2.8 T AEJ - Minolta MC 24mm f 2.8 - Canon LTM 85 1.9- Canon LTM 85mm 1.9 convert to EOS - Rodenstock Heligon 50 1.9 - Color Skopar 50 2.8 & MAte Box & filters 4X4
Contax RTS II y Minolta SRT 303 - 28-135 3.6 Tokina - Minolta MD 45 f2.0 - Minolta Zoom 80 200 4.5 (Leica)
www.isgleasphoto.com
The life is more easy with this forum .... |
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Pancolart
Joined: 04 Feb 2008 Posts: 3702 Location: Slovenia, EU
Expire: 2013-11-18
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Posted: Sun Oct 31, 2010 12:35 pm Post subject: |
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Pancolart wrote:
Hula, that really looks the same. Maybe area outside sensor differs more. Can you show a photo of lens aperture at F1.2 and F2.0? Did you check if your adapter interferes with aperture pin? _________________ ---------------------------------
The Peculiar Apparatus Of Victorian Steampunk Photography: 100+ Genuine Steampunk Camera Designs https://www.amazon.com/dp/B0B92829NS |
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8310
Joined: 05 Jun 2010 Posts: 123
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Posted: Sun Oct 31, 2010 1:11 pm Post subject: |
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8310 wrote:
I suppose you checked that the aperture really does close down to a circle of roundabout a bit less than half the diameter than at 1.2, right?
What camera are you using? Depending on the angle of the light rays hitting the sensor at 1.2, it might have to do something with that sort of thing:
http://www.luminous-landscape.com/essays/an_open_letter_to_the_major_camera_manufacturers.shtml
I have to admit that I have not yet really thought through that whole story and all the consequences that come with it, but on a first glimpse, it looks like it could be your sensors fault. |
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Orio
Joined: 24 Feb 2007 Posts: 29545 Location: West Emilia
Expire: 2012-12-04
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Posted: Sun Oct 31, 2010 1:44 pm Post subject: |
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Orio wrote:
It is not identical! I see a clearly visible difference. _________________ Orio, Administrator
T*
NE CEDE MALIS AUDENTIOR ITO
Ferrania film is reborn! http://www.filmferrania.it/
Support the Ornano film chemicals company and help them survive!
http://forum.mflenses.com/ornano-chemical-products-t55525.html |
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fatdeeman
Joined: 13 Jun 2009 Posts: 780 Location: UK
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Posted: Sun Oct 31, 2010 2:05 pm Post subject: |
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fatdeeman wrote:
I can see a difference, to me it seems noticeably smoother at f/2 _________________ - Dave
www.lensporn.net
www.flickr.com/photos/fatdeeman/
DSLR: Canon EOS 60D, Samsung GX-1S (Pentax *ist DS2)
Mirrorless: Panasonic DMC-G1, Sony NEX-5N
Compact: Canon PowerShot G3
Lenses:
Wide: Tokina RMC 28mm F/2.8, Tamron Adaptall 2 28mm F/2.5, Sun Optical 28mm F/2.5, Super paragon 28mm F/2.8, Sigma filtermatic 24mm F/2.8, Fujinon 35mm F/2.8, Sun Optical 35mm F/2.8
Standard: Industar 50-2, Helios 44-2, Helios 44M, Helios 44M-3, Pentax-M 50mm F/1.4, Pentax-M 50mm F/1.7, Pentax-M 50mm F/2, Ricoh 50mm F/1.7, Chinon 50mm F/1.7
Tele: Pentacon 135mm F/2.8, Pentacon 200mm F/3.5, Optomax 200mm f/3.5, Sun Optical 135mm F/3.5, Soligor 350mm F/5.6
Zoom: Tokina 28-70mm f/3.5-4.5 SZ-X270 SD, Sigma Zoom Pi 35-200mm F4-5.6, Sun Optical 28-80mm F/3.5-4.5, Sunagor 80-205mm F/3.8, Tokina RMC 80-200mm F/4, Vivitar 70-150mm F/3.8, Tamron 95-205mm F/6.3, Tamron Adaptall 28-200mm F/3.8-5.6 LD Aspherical, Tokina RMC 70-210mm F/3.5
Mirror: Falcon (Samyang) 800mm F/8, MTO-11CA 1000mm F/10, Tamron Adaptall 2 500mm F/8
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Ivan Lee
Joined: 03 Feb 2008 Posts: 230 Location: Rio de Janeiro - Brazil
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Posted: Sun Oct 31, 2010 9:17 pm Post subject: |
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Ivan Lee wrote:
Hey guys...some new discoverings today
First, the picture of both lenses at f/2, the MD 50 and the MC 58
My 58mm Rokkor is converted to M42 and I use it with a M42-m4/3s adapter in my GH1.
And today I shot some different pictures and indeed the f/2 picture has a different bokeh. BUT, I was right about the 2/3 of stop difference...
Actually, is exactly like this: from wide open to f/2 (2/3s of stop) and from f/2 to f/2.8 is 1 1/3s of stop! then from f/2.8 to f/4 is 1 stop difference...
1/2500s to 1/1600s (2/3 stop) then from 1/1600s to 1/640s (1 1/3 stop)
look at the photos from today:
f/1.2 - 1/2500s
f/2 - 1/1600s
f/2.8 - 1/640s
So I'm sure that the f/2 setting is not f/2 for real... maybe a problem with the aperture?
And the MD 50mm looks sharper at f/2 than the MC 58mm at f/2... but the 58mm is absoluttely sharper at f/1.2 than the MD... interesting... _________________ Ivan Lee Barcellos - Director of Photography
www.planoconjunto.com.br
Sony A7s
Lumix GH3
Minolta MC: Minolta MC 24/2.8 - Minolta MD 28/2 - Minolta MC 35/1.8 - Minolta MC 35/2.8 - Minolta MD 50/1.2 - Minolta MD Macro 50/3.5 - Minolta MD 100/2.5
Konica AR: Hexanon 28/3.5 - Hexanon 50/1.7 - Hexanon 57/1.4
M42: Industar 50-2 - CZ Pancolar 50/1.8
Olympus OM: Zuiko Auto-Macro 50/3.5 - Vivitar 28/2 Close Focus |
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Ivan Lee
Joined: 03 Feb 2008 Posts: 230 Location: Rio de Janeiro - Brazil
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Posted: Sun Oct 31, 2010 9:25 pm Post subject: |
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Ivan Lee wrote:
Pancolart wrote: |
Hula, that really looks the same. Maybe area outside sensor differs more. Can you show a photo of lens aperture at F1.2 and F2.0? Did you check if your adapter interferes with aperture pin? |
I promisse that I'll shot some better pictures of the lens wide-open and at f/2... this one is just to have an idea of the opening of the aperture at f/2...
the adapter does not interfere with the pin... _________________ Ivan Lee Barcellos - Director of Photography
www.planoconjunto.com.br
Sony A7s
Lumix GH3
Minolta MC: Minolta MC 24/2.8 - Minolta MD 28/2 - Minolta MC 35/1.8 - Minolta MC 35/2.8 - Minolta MD 50/1.2 - Minolta MD Macro 50/3.5 - Minolta MD 100/2.5
Konica AR: Hexanon 28/3.5 - Hexanon 50/1.7 - Hexanon 57/1.4
M42: Industar 50-2 - CZ Pancolar 50/1.8
Olympus OM: Zuiko Auto-Macro 50/3.5 - Vivitar 28/2 Close Focus |
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Ivan Lee
Joined: 03 Feb 2008 Posts: 230 Location: Rio de Janeiro - Brazil
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Posted: Sun Oct 31, 2010 9:27 pm Post subject: |
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Ivan Lee wrote:
8310 wrote: |
I suppose you checked that the aperture really does close down to a circle of roundabout a bit less than half the diameter than at 1.2, right?
What camera are you using? Depending on the angle of the light rays hitting the sensor at 1.2, it might have to do something with that sort of thing:
http://www.luminous-landscape.com/essays/an_open_letter_to_the_major_camera_manufacturers.shtml
I have to admit that I have not yet really thought through that whole story and all the consequences that come with it, but on a first glimpse, it looks like it could be your sensors fault. |
That's some interesting reading...I'll check this out later today!
thanks! _________________ Ivan Lee Barcellos - Director of Photography
www.planoconjunto.com.br
Sony A7s
Lumix GH3
Minolta MC: Minolta MC 24/2.8 - Minolta MD 28/2 - Minolta MC 35/1.8 - Minolta MC 35/2.8 - Minolta MD 50/1.2 - Minolta MD Macro 50/3.5 - Minolta MD 100/2.5
Konica AR: Hexanon 28/3.5 - Hexanon 50/1.7 - Hexanon 57/1.4
M42: Industar 50-2 - CZ Pancolar 50/1.8
Olympus OM: Zuiko Auto-Macro 50/3.5 - Vivitar 28/2 Close Focus |
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ZoneV
Joined: 09 Nov 2009 Posts: 1632 Location: Germany
Expire: 2011-12-02
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Posted: Mon Nov 01, 2010 9:10 am Post subject: |
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ZoneV wrote:
We had this microlens problem here before:
http://forum.mflenses.com/fast-lenses-and-microlenses-t33709.html
In your 4/3 camera it could be, that the microlenses are optimized for telecentric lenses - and thet the exposture and depth of field difference between f/2.0 and f/1.4 for example is smaller than expected.
But on the other hand the bokeh rendering could be a bit smoother because of this. _________________ Camera modification, repair and DIY - some links to look through: http://www.4photos.de/camera-diy/index-en.html
I AM A LENS NERD!
Epis, Elmaron, Emerald, Ernostar, Helioplan and Heidosmat.
Epiotar, Kameraobjektiv, Anastigmat, Epis, Meganast, Magnagon, Quinar, Culmigon, Novotrinast, Novflexar, Colorplan, Sekor, Kinon, Talon, Telemegor, Xenon, Xenar, Ultra, Ultra Star. Tessar, Janar, Visionar, Kiptar, Kipronar and Rotelar.
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Ivan Lee
Joined: 03 Feb 2008 Posts: 230 Location: Rio de Janeiro - Brazil
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Posted: Mon Nov 01, 2010 3:56 pm Post subject: |
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Ivan Lee wrote:
8310 wrote: |
I suppose you checked that the aperture really does close down to a circle of roundabout a bit less than half the diameter than at 1.2, right?
What camera are you using? Depending on the angle of the light rays hitting the sensor at 1.2, it might have to do something with that sort of thing:
http://www.luminous-landscape.com/essays/an_open_letter_to_the_major_camera_manufacturers.shtml
I have to admit that I have not yet really thought through that whole story and all the consequences that come with it, but on a first glimpse, it looks like it could be your sensors fault. |
This is so weird... How can my camera know if I'm using a large aperture if I use manual lenses 90% of the time?
And testing the MD 50mm f/1.2 with my GH1, the difference between f/1.2 - f/2 and so on are exactly 1 stop difference (I plan to test this later with a gray card to be more acurate) _________________ Ivan Lee Barcellos - Director of Photography
www.planoconjunto.com.br
Sony A7s
Lumix GH3
Minolta MC: Minolta MC 24/2.8 - Minolta MD 28/2 - Minolta MC 35/1.8 - Minolta MC 35/2.8 - Minolta MD 50/1.2 - Minolta MD Macro 50/3.5 - Minolta MD 100/2.5
Konica AR: Hexanon 28/3.5 - Hexanon 50/1.7 - Hexanon 57/1.4
M42: Industar 50-2 - CZ Pancolar 50/1.8
Olympus OM: Zuiko Auto-Macro 50/3.5 - Vivitar 28/2 Close Focus |
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AhamB
Joined: 22 Jun 2008 Posts: 733 Location: Germany
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Posted: Mon Nov 01, 2010 6:44 pm Post subject: |
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AhamB wrote:
Ivan Lee wrote: |
This is so weird... How can my camera know if I'm using a large aperture if I use manual lenses 90% of the time? |
It can't, and that's why you get less exposure at f/1.2 than at f/2. If your camera would know (through electronic coupling), it could apply the extra sensor gain at f/1.2 to equalize the exposure with that at f/2.
The test results in that article from the luminous landscape must have been performed with the Canon EF 50 or 85 f/1.2L and similar f/1.4 autofocus lenses for the Nikon and Sony cameras. |
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francotirador
Joined: 17 Sep 2009 Posts: 894
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Posted: Sun Nov 14, 2010 3:58 am Post subject: |
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francotirador wrote:
The F2 in your 58 is not real, I have compared with mine. Has the same difference as your 50mm. _________________ Canon 5D II-Sony nex 6
Canon L 80-200 f 2.8 - Canon L 135 f2 - Canon FD 135/2.5 convert to EOS - Yashica 50 1.4 ML - Canon FD 50 1.2 - Distagon 35mm 2.8 T AEJ - Minolta MC 24mm f 2.8 - Canon LTM 85 1.9- Canon LTM 85mm 1.9 convert to EOS - Rodenstock Heligon 50 1.9 - Color Skopar 50 2.8 & MAte Box & filters 4X4
Contax RTS II y Minolta SRT 303 - 28-135 3.6 Tokina - Minolta MD 45 f2.0 - Minolta Zoom 80 200 4.5 (Leica)
www.isgleasphoto.com
The life is more easy with this forum .... |
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