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newton
Joined: 10 Mar 2011 Posts: 343 Location: USA
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Posted: Sat Apr 02, 2011 4:07 pm Post subject: Are mirror less camera and lens systems superior? |
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newton wrote:
I am wondering what the role of mirrors have in detracting from image quality, if at all, and if mirror less cameras are really superior, when considering the entire lens system. |
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scsambrook
Joined: 29 Mar 2009 Posts: 2167 Location: Glasgow Scotland
Expire: 2011-11-18
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Posted: Sat Apr 02, 2011 4:29 pm Post subject: |
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scsambrook wrote:
Well, the moving mirror in a typical SLR plays no part in forming the image on film or sensor so it can't detract from quality - unless its action is so violent as to cause shake or vibration
However, pellicle mirrors, which reflect some light into a viewfinder system and allow the majority of it to pass through to the film or sensor, could become dirty and so affect the image. That did happen with the old Canon Pellix back in the 1960s/70s.
The new generation of mirrorless cameras has advantages of compactness and lightweight, as well as allowing the lens designer potentially greater freedom in his/her (i.e the computer's) work. _________________ Stephen
Equipment: Pentax DSLR for casual shooting, Lumix G1 and Fuji XE-1 for playing with old lenses, and Leica M8 because I still like the optical rangefinder system. |
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RioRico
Joined: 12 Mar 2010 Posts: 1120 Location: California or Guatemala or somewhere
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Posted: Sat Apr 02, 2011 5:17 pm Post subject: |
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RioRico wrote:
For ultimate image quality (IQ), shun all mirrors, lenses, prisms, everything. Use a finely-made pinhole projecting onto a large-format frame. Oops, that is not convenient. So, use a film rangefinder camera with no mirrors nor prisms, just a good lens, maybe a 50/3.5 Elmar. Oh no, film isn't digital. So use a phone.cam, both digital and convenient, and to hell with IQ!
No, as scsambrook said, the mirror (or lack thereof) has no impact on IQ. If it did, professionals in fields where IQ is critical would throw away their crop dSLRs and use only MILCs. Check the astrophotography and foresnics forums and see whether MILCs have taken over. _________________ Too many film+digi cams+lenses, oh my -- Pentax K20D, K-1000, M42s, more
The simple truth is this: There are no neutral photographs. --F-Stop Fitzgerald
Last edited by RioRico on Sun Apr 03, 2011 10:33 am; edited 1 time in total |
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wupdigoj
Joined: 18 Mar 2010 Posts: 85
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Posted: Sun Apr 03, 2011 9:50 am Post subject: |
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wupdigoj wrote:
Mirrors have obviously no direct impact in IQ. However, they impose some restrictions in the lenses design: the minimun distance between the rear element and the focal plane. So theorically and specially in short focal lengths, mirrorless cameras have some advantage.
Javier |
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AhamB
Joined: 22 Jun 2008 Posts: 733 Location: Germany
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Posted: Sun Apr 03, 2011 10:01 am Post subject: |
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AhamB wrote:
What Javier is saying. The long register distance of SLR's force lens designers to make asymmetric "retrofocus" designs for wideangle lenses. I've read they're basically inverted telephoto designs. Apparently this makes it more difficult to correct CA and have good corner sharpness.
Lenses for mirrorless (one word) cameras or rangefinders don't have this problem, but for digital sensors they have another problem, being the very oblique angles of light which the sensor has trouble collecting from a lens that is very close to it. Leica/Kodak(?) has mitigated this problem to some degree with offset micro lenses, but there is still a problem with color shift, especially when you use Zeiss ZM or Voigtländer lenses on the M9.
Other mirrorless cameras such as the Sony NEX can get smeared corners at wide apertures with lenses of 28mm and wider, and varying amounts of color shift (cyan/magenta color cast in different parts of the frame). |
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jun
Joined: 25 Jan 2011 Posts: 54 Location: Philippines
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Posted: Sun Apr 03, 2011 10:13 am Post subject: why only now? |
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jun wrote:
am i missng something with regards to the use of the mirrors in traditional dslr?
the dslr has been around for a decade or so? why is it that it is only in the past 2-3 years did they eliminate the mirror?
was there a technology hurdle somewhere that prevented the mirrorless system?
is the viewfinder the only use of a traditional mirror system? _________________ mc rokkor 58 f1.4, mc rokkor 135 f2.8, canon fd 50 f1.4, yashica ml 50 f1.9, sigma 80-200 f4, tokina 80-200 f4, sony nex 16mm f2.8, sony alpha 18-70 f3.5-5.6, pentax smc f 35-70mm f3.5-5.6, canon efs 18-55 f3.5-5.6, tokina 28 f2.8, canon fl 58 f1.2 |
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ManualFocus-G
Joined: 29 Dec 2008 Posts: 6622 Location: United Kingdom
Expire: 2014-11-24
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Posted: Sun Apr 03, 2011 10:47 am Post subject: |
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ManualFocus-G wrote:
Well, tradionally the main manufacturers hadn't produced electronic viewfinders and screens capable of keeping up with the action for a start. _________________ Graham - Moderator
Shooter of choice: Fujifilm X-T20 with M42, PB and C/Y lenses
See my Flickr photos at http://www.flickr.com/photos/manualfocus-g |
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RioRico
Joined: 12 Mar 2010 Posts: 1120 Location: California or Guatemala or somewhere
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Posted: Sun Apr 03, 2011 10:55 am Post subject: Re: why only now? |
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RioRico wrote:
jun wrote: |
was there a technology hurdle somewhere that prevented the mirrorless system? |
From what I have read, I think the hurdle is the development of an acceptable EVF (electronic viewfinder).
Quote: |
is the viewfinder the only use of a traditional mirror system? |
Well, yes. We have various ways of viewing a scene we wish to photograph. Past, present, and future cameras may such devices as:
* nothing; just aim and hope
* a wire-frame sportsfinder
* a simple rectangular tube
* simple uncoupled viewfinder
* a coupled rangefinder system
* view-camera groundglass back
* waist-level reflex groundglass.
* reflex pentaprism or pentamirror
* electronic viewfinder, analog or digital
* super-EVF: LiveView LCD screen
* EVF data stream to VR goggles
* holographic HUD (heads-up display)
There are probably a couple others I have forgotten. The purpose of any of these is to show you your subject. With reflex cameras, the image bounces off a mirror and maybe through various optics before reaching your eye. Some portion of that image may be diverted for light metering or focus control. But a reflex mirror's job is just to let you see exactly what the camera frame (film or digital) will see. _________________ Too many film+digi cams+lenses, oh my -- Pentax K20D, K-1000, M42s, more
The simple truth is this: There are no neutral photographs. --F-Stop Fitzgerald |
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AhamB
Joined: 22 Jun 2008 Posts: 733 Location: Germany
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Posted: Sun Apr 03, 2011 3:57 pm Post subject: Re: why only now? |
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AhamB wrote:
jun wrote: |
am i missng something with regards to the use of the mirrors
is the viewfinder the only use of a traditional mirror system? |
Phase detect autofocus. On all AF (D)SLR's the reflex mirror is partially translucent and there's a little mirror (the "submirror") behind the main mirror which sends some light to the AF sensor in the bottom of the mirror box.
Mirrorless camera's can use a rangefinder system for manual focus, or contrast detect AF, which is slower than phase detect (up to now). Phase detect measures distance, which contrast detect cannot, so contrast detect can hunt in the wrong direction first. |
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