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Author Topic: D800 mirror vibration - myth buster surprise  (Read 14176 times)

Kirk Gittings

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Re: D800 mirror vibration - myth buster surprise
« Reply #20 on: April 28, 2013, 11:52:57 AM »

Kirk, the implication that anything other than made with a 4x5 will look like crap up close is a bit silly.  

I don't 'prevent' people from looking closely.  But the simple fact is that most people don't.  The simple fact is that the concept of 'normal viewing distance' has developed for a reason.  

I ask about 'real' images because test charts at 300% or 400% aren't overly indicative of much.  People in images move.  Trees, leaves, grass, move.  At 300% or 400% even a tiny amount of movement will likely be picked up.  Will it be evident in a print?  Even quite a large print?  Call me crazy but I'm one of those photographers who still believe that the ultimate presentation of a photograph is a print, not something on a computer screen.  

Blow a film image up far enough and you get nothing but a mess of grain up close, even at reasonable viewing distances in some cases.  We didn't object to it then the way we do now.  Medium format cameras have far bigger mirrors and much more significant mirror slap than a 35mm format DSLR.  

Actually film grain, if rendered sharp, is very beautiful up close (low res digital not), even 35mm printed large. When I go to shows (my own and others). and I go to tons of them, I always see people sticking their nose up to prints AND stepping back to get the full view. It appears to me (and I have been at this for 40+ years with almost 100 of my own exhibits) that this notion of normal viewing distance has grown out of the early and very crappy early digital prints-a rational because the prints fell appart up close. I never heard of this concept before digital.
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RFPhotography

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Re: D800 mirror vibration - myth buster surprise
« Reply #21 on: April 29, 2013, 08:20:04 AM »

I've never considered grain to be beautiful.  Then again, Kim Kardashian turns a lot of cranks but I find her quite revolting.  ;D

The concept of 'normal viewing distance' has been around far longer than the early days of digital prints.  The concept of depth of field takes into account the viewing distance.  So the idea has been around for a good many years.
« Last Edit: April 29, 2013, 08:52:42 AM by BobFisher »
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MarkL

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Re: D800 mirror vibration - myth buster surprise
« Reply #22 on: April 29, 2013, 01:29:58 PM »

I have always found this a funny concept, which is why I mainly shoot 4x5 for my personal work. How do you prevent people from looking at your prints so close and having them look like crap? Or do you post a disclaimer?

Agreed. I don't like over-enlarged prints at exhibition where the detail has fallen apart which is all too common.
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AlfSollund

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Re: D800 mirror vibration - myth buster surprise
« Reply #23 on: April 29, 2013, 02:33:07 PM »

Thanks for sharing. Have you compared with sandbag, beanbag or similar for support?
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Kirk Gittings

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Re: D800 mirror vibration - myth buster surprise
« Reply #24 on: May 01, 2013, 05:31:43 PM »

I've never considered grain to be beautiful.  Then again, Kim Kardashian turns a lot of cranks but I find her quite revolting.  ;D

The concept of 'normal viewing distance' has been around far longer than the early days of digital prints.  The concept of depth of field takes into account the viewing distance.  So the idea has been around for a good many years.

Well I don't ever remember hearing it till digital and I have taught photo at workshops and universities (5) since about 1980ish.
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telyt

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Re: D800 mirror vibration - myth buster surprise
« Reply #25 on: May 01, 2013, 06:08:21 PM »

Well I don't ever remember hearing it till digital and I have taught photo at workshops and universities (5) since about 1980ish.

I heard of it in the early 1970s.
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Gigi

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Re: D800 mirror vibration - myth buster surprise
« Reply #26 on: May 01, 2013, 07:18:55 PM »

two ideas:

- less vibration: MLU and leaf shutters
- dampening with mass: sandbags, hang weight from tripod.

Also, no use of center columns - they are cantilevers, and make things worse.
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Geoff
Re: D800 mirror vibration - myth buster surprise
« Reply #27 on: May 01, 2013, 07:43:48 PM »

Having a background in vibration control I have several comments
1. to reduce vibration you want a "shock absorber" that damps vibrations by turning kinetic energy into heat not a "spring" (capacitor) that stores energy and releases it later in time.
Drop Sorbothane on the floor and it bounces, it is not a good material for vibration control, proper companies like EAR and Soundcoat do make good vibration isolation materials
2. I designed a vibration isolation mount for my tripod and found the following:
a. mirror lockup (liveview) and a cable release was just as effective
b. mass damping by hanging a backpack from your tripod was very effective
c. the vibration isolation devise would let the camera sag a bit if it was pointed up or down and made composition a pain.
3. The most practical solution is a sturdy tripod with a hook, hang your backpack on it, use liveview and a cable release
4. I wish manufacturers would use some constrained layer damping materials around the mirror box it would help
Marc
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Marc McCalmont

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Re: D800 mirror vibration - myth buster surprise
« Reply #28 on: May 01, 2013, 08:23:54 PM »


b. mass damping by hanging a backpack from your tripod was very effective


Thanks for the info. Does anybody else find hanging weight on the tripod hook beneficial in vibration reduction? Are there any studies on this?
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bill t.

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Re: D800 mirror vibration - myth buster surprise
« Reply #29 on: May 01, 2013, 11:22:10 PM »

In my motion control camera days I found that draping long lenses and motion picture camera bodies with large plastic bags filled with Liquid Prell shampoo could very effectively reduce acceleration induced lurches and vibrations in general.  If Prell produces any Sorbathane-like recoil, it is very slow on the draw.  Camera systems draped with bags green ooze also make a good conversation piece on the set.  Not making this up.  Someday I'll tell you about bungee-assisted whip-pans.

Here a demonstration of Liquid Prell's superior damping characteristics.
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