Luminous Landscape Forum

Equipment & Techniques => Cameras, Lenses and Shooting gear => Topic started by: GaRP on April 16, 2009, 11:30:23 am

Title: Mirror Lock-up is a bigger deal than previously thought
Post by: GaRP on April 16, 2009, 11:30:23 am
I found this while surfing this AM.

http://techon.nikkeibp.co.jp/english/NEWS_...0090413/168663/ (http://techon.nikkeibp.co.jp/english/NEWS_EN/20090413/168663/)

Highlights directly from the article:

The results of measurements using the new tool are as follows. The resolution of an SLR camera was substantially reduced to 1/4 or lower by the mirror shock (vibration generated when the mirror bounces up).
Next, it was confirmed that the vibration generated by releasing the shutter remains even when a picture is taken after a certain period of time from the mirror lockup to prevent a mirror shock.
Then, the Nishi Lab and Tani Electronics found that camera shake significantly worsens when a lighter tripod (approx 1.5kg) is used. Also, they conducted a quantitative investigation about the influence of the installation direction of the tripod.
"There is no point in enhancing resolution unless we take some measures to reduce the vibration of a camera unit as a whole including a tripod," said Kazuki Nishi of UEC.
When a tripod is used, the above measurements were carried out after disabling the image stabilizer, as directed in instruction manuals of cameras and lenses. And, to make sure, the researchers conducted the measurements using several cameras with the image stabilizer function turned on and confirmed that camera shake worsens.

This may be old information but I could find no other references on the forum.
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: EricV on April 16, 2009, 12:17:02 pm
A fancy lab is hardly needed to see the effects of vibration.  Michael recently suggested the simple demonstration of attaching a laser pointer to the camera and watching the beam vibrate as the mirror bounces or the shutter is tripped.  An even better demonstration would be to mount the laser pointer off the camera, pointing stably at a distant wall in a dark room, then take pictures of the laser dot under varying conditions and examine the images at high magnification.
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: 250swb on April 16, 2009, 05:06:50 pm
Mirror lockup, or at least a shutter delay, has always been a big deal. Which is why it should be higher in most camera menus. Unfortunately it isn't 'sexy' because mirror lockup implies negative overtones that you need a special function to stop the camera 'f ing' up your photo's.

Steve
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: DarkPenguin on April 16, 2009, 05:34:08 pm
Quote from: 250swb
Mirror lockup, or at least a shutter delay, has always been a big deal. Which is why it should be higher in most camera menus. Unfortunately it isn't 'sexy' because mirror lockup implies negative overtones that you need a special function to stop the camera 'f ing' up your photo's.

Steve

What!?!?

Are you sure it just isn't something that most people don't use and never would no matter how easy you make it for them?  kind of like using a tripod?
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: Nick Rains on April 17, 2009, 12:57:16 am
Quote from: DarkPenguin
What!?!?

Are you sure it just isn't something that most people don't use and never would no matter how easy you make it for them?  kind of like using a tripod?

LOL - yes indeed.

I remember watching a guy shoot images of a rainforest waterfall. He stood there with his camera, taking pics in the deepest shade and then left,  with a tripod still strapped to his backpack. It was a 10k round trip to this waterfall - WTF!

I don't think MLU would have helped.
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: BernardLanguillier on April 17, 2009, 01:27:07 am
Quote from: GaRP
http://techon.nikkeibp.co.jp/english/NEWS_...0090413/168663/ (http://techon.nikkeibp.co.jp/english/NEWS_EN/20090413/168663/)

Any idea whether the original Japanese article is available online? This abstract is too vague to figure out the details of their findings.

My personnal experience shows:
- Tripod without MLU is the stupidest thing to do, whatever the shutter speed
- Handheld without MLU is a reasonnable option when the shutter speed is high enough
- The weight of the tripod in itself means little without looking at its vibration behavior
- The shutter itself is also an important source of vibration when it is large (like plane shutter MF for instance)

Cheers,
Bernard
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: Nick Rains on April 17, 2009, 02:11:41 am
I don't doubt the theory of this but I've just been tinkering around with a laser pointer...35mm camera only as I don't have an MF system to hand (unless I used my old RZ).

Canon 400D (lightest body I could find), 17-40L.
Gitzo 4 section carbon fibre tripod with full leg extension (2540LVL)
Crappiest tripod head I could dig out of my cupboard, a Manfrotto 141RC with a small cork faced QR plate.

Using 10 sec self timer and no MLU and at a range of 10m I got a deflection of less than one mm on shutter firing at 1/15th sec which would be one of the worst shutter speeds to use (I tried other shutter speeds and there's not much difference). That's less than 1:10000. Not sure what that is in angular deflection but it's not much. Using MLU reduced that to zero, or certainly not discernible to the naked eye.

The worst result I could get was with a 5D on a Kirk B+S with the tripod centre column at full extension (!). Then the deflection was about 1.5mm. With MLU it was barely perceptible.

What I did notice though was that the barest touch of the tripod sent the spot wiggling around like mad.

My conclusions for now are that in the absence of wind even a half decent tripod holding a DSLR it will be completely stable if you use MLU and an electronic cable release. Even without MLU it's still almost perfect. Shutter bounce, in these two cameras at least, has negligible effect. But if you use your finger without MLU then you will be very likely to get an soft image, and with a tele lens this is obviously magnified.

When I get my hands on a medium format system I'll try the same test and see how it goes.
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: Henry Goh on April 17, 2009, 02:13:30 am
Quote from: BernardLanguillier
Any idea whether the original Japanese article is available online? This abstract is too vague to figure out the details of their findings.

My personnal experience shows:
- Tripod without MLU is the stupidest thing to do, whatever the shutter speed
- Handheld without MLU is a reasonnable option when the shutter speed is high enough
- The weight of the tripod in itself means little without looking at its vibration behavior
- The shutter itself is also an important source of vibration when it is large (like plane shutter MF for instance)

Cheers,
Bernard

Hi Bernard,

May I clarify: are you saying w/o MLU even at higher speeds on a tripod, you are seeing image degradation from vibrations?  Is this observation from all cameras?

Thank you.


Title: Mirror Lock-up is a bigger deal than previously thought
Post by: David Sutton on April 17, 2009, 02:35:05 am
So many variables to consider when trying to get really sharp images. For the life of me I've never been able to get the laser pointer thing to work. Even running the beam back and forth across the room with mirrors to amplify any movement. But I have seen obvious horizontal blur in an image, even with MLU, when using a tripod on a wooden floor at shutter speeds of about half a second (part of the same experiment). A bean bag on the camera solved the problem. I've always felt my tripod to be a little lightweight ( Velbon Sherpa) but since fitting it with a hook and hanging my backpack there, the whole thing now feels rock-solid. But for anything under about 1/30th second I'd still use the beanbag if handy.
David
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: Henry Goh on April 17, 2009, 02:49:31 am
Can you guys please try this.  I don't have a lightweight tripod so need you to test:

Instead of hanging heavy bags or other things under your CF tripods, could you hang a bottle of water say 1 litre or 1.5 litre bottle of Coke or something.  Now repeat your tests and see if you find significant improvement.

Please report.

Thanks.
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: Ray on April 17, 2009, 06:40:26 am
Quote from: BernardLanguillier
My personnal experience shows:
- Tripod without MLU is the stupidest thing to do, whatever the shutter speed

My experience is quite different, Bernard. I've never found MLU to be necessary outside of a shutter speed range of 2 seconds to 1/60th. The most critical shutter speeds are 1/15th to 1/30th. At 1/60th and 2 seconds, the benefits of MLU would only be noticeable (if at all) at print sizes far greater than you would likely make, or at 200% on the monitor.

I've heard reports of images from long telephoto lenses benefitting from MLU with shutter speeds as fast as 1/125th. But I've never experienced such a benefit with my 100-400 IS. On the other hand, that's not a particularly sharp lens, so maybe a razor sharp long telephoto actually can benefit from MLU at 1/125th.

I once tested the effects of MLU on my Canon 20D with 50/1.8 II lens, using a lightweight travel tripod and remote cord. I could not detect any benefit from MLU at any shutter speed, yet when using the 5D with the same lens on the same tripod, same position and same target, there was a very noticeable benefit to MLU at 1/30th.

The Canon 20D has a very noisy mirror slap. My theory is that the energy of low frequency and inaudible vibrations which would normally cause a problem with most DSLRs when the mirror is rapidly lifted, has been transformed into less harmful, higher frequency vibrations on the 20D. Whilst such higher frequency vibrations are very audible, they are too high to cause physical vibration of the camera.
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: BernardLanguillier on April 17, 2009, 06:50:28 am
Quote from: Henry Goh
Hi Bernard,

May I clarify: are you saying w/o MLU even at higher speeds on a tripod, you are seeing image degradation from vibrations?  Is this observation from all cameras?

Yes, I have not done rigorous tests on this, and have not taken a single shot on tripod without MLU for years, but I did see such things a few years back (I believe with a SLR/n at the time).

Regards,
Bernard

Title: Mirror Lock-up is a bigger deal than previously thought
Post by: JeffKohn on April 17, 2009, 01:22:16 pm
Quote from: Henry Goh
Hi Bernard,

May I clarify: are you saying w/o MLU even at higher speeds on a tripod, you are seeing image degradation from vibrations?  Is this observation from all cameras?

Thank you.
Not to speak for Bernard, but if you're going to take the trouble to use a tripod and cable release or timer, there's really no reason _not_ to also use MLU if your camera supports it.
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: Ray on April 18, 2009, 06:25:22 pm
Quote from: JeffKohn
Not to speak for Bernard, but if you're going to take the trouble to use a tripod and cable release or timer, there's really no reason _not_ to also use MLU if your camera supports it.

That's not necessarily true if your camera does not support Live View. If your camera does support Live View, and, if you go to the trouble of using a tripod and cable release, you might as well enable Live View so you can be sure of accurate focussing. In which case, also enabling MLU is no longer necessary because in Live View mode the mirror is already flipped.

However, if your camera does not support Live View (as the Sony A900 doesn't), then there may be circumstances when using MLU for no good purpose puts you at a disadvantage. Consider the procedure. Press the shutter button once to flip the mirror. Wait a couple of seconds for any vibrations to subside. Press the shutter again to take the shot. There's at least a 2 second period during which time you are unable to see through the viewfinder. Any person or animal in the scene, buffalo or large bird, might suddenly turn its/his/her head during that 2 or 3 second interval. Photgraphy is often about capturing the moment.

Consider also the cumbersome procedure of autobracketing exposure with MLU enabled. It could take up to 10 seconds to take 3 shots even with fairly fast exposures. A lot can happen in 10 seconds.


Title: Mirror Lock-up is a bigger deal than previously thought
Post by: Peter McLennan on April 19, 2009, 11:50:33 am
Quote from: Ray
...Consider also the cumbersome procedure of autobracketing exposure with MLU enabled. It could take up to 10 seconds to take 3 shots even with fairly fast exposures. A lot can happen in 10 seconds.


Indeed, Ray.  It's a frequent annoyance for those of us addicted to HDR.  Clouds move much faster than you think.

Perhaps it's time to reconsider the mechanical shutter.
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: JeffKohn on April 19, 2009, 01:08:16 pm
Quote from: Ray
That's not necessarily true if your camera does not support Live View. If your camera does support Live View, and, if you go to the trouble of using a tripod and cable release, you might as well enable Live View so you can be sure of accurate focussing. In which case, also enabling MLU is no longer necessary because in Live View mode the mirror is already flipped.
I can understand how you might feel that way shooting Canon. In Nikon-land, live-view is no substitute for MLU, because with live-view the camera still drops the mirror down before taking the exposure and then operates as normal. This means that mirror-slap can be even more of an issue with live-view than with out. Stupid I know, but that's how it works. So my habit is to use live-view for focusing, then switch to MLU mode to take the exposure.

Quote
However, if your camera does not support Live View (as the Sony A900 doesn't), then there may be circumstances when using MLU for no good purpose puts you at a disadvantage. Consider the procedure. Press the shutter button once to flip the mirror. Wait a couple of seconds for any vibrations to subside. Press the shutter again to take the shot. There's at least a 2 second period during which time you are unable to see through the viewfinder. Any person or animal in the scene, buffalo or large bird, might suddenly turn its/his/her head during that 2 or 3 second interval. Photgraphy is often about capturing the moment.
I don't see this as much of an issue for single exposures. You flip the mirror up in anticipation of the shot. I'm not suggesting MLU be used for action photography or BIF's, but for landscapes where you care about the getting the sharpest results possible (often at slowish shutter speeds), MLU becomes important.
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: JeffKohn on April 19, 2009, 01:15:11 pm
Quote
Perhaps it's time to reconsider the mechanical shutter. rolleyes.gif
I wouldn't want to use an EVF camera for people, action, etc. But for landscapes I would definitely consider a live-view only camera with no mirror and an electronic shutter. Not only would it eliminate shutter slap but it should also make it possible to designer better wideangle lenses if there's no mirror clearance to worry about. Just think how nice it would be to shoot autobracketed exposures at 5fps without having to worry about any mirror- or shutter-induced camera shake.
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: Rob C on April 19, 2009, 03:15:53 pm
Iīm heartened to see that others have experienced the same strange effects that I have too: several different tests with cameras on tripod and mirror locked up or not locked up have not always delivered the expected results of the images WITH the mirror locked up being always better than the others.

As a matter of principle, when mlu is possible Iīd use it, but it is no guarantee of best results. In fact, I have found that if I actually put some pressure down on the camera with one hand and trip the shutter with the other, a fairly good result will follow.

But with all of this, I believe that Bernard touched on a vital point: the intrinsic vibration-style of the tripod itself. And that seems to vary somewhat according to the material upon which its feet are based too: very hard floor tiles, for example, appear to set in motion a ībrittleī sort of mechanics whereby the tripod feels very stiff but very movement-prone. Odd; has anybody else found this too?

Perhaps the worst case Iīve come across has been with the Pentax 67 ll, where with mirror locked up, on a heavy Gitzo, the shutter has bounced so much that the edges of the frame have been hopeless. Didnīt keep the camera long... a further big loss of money.

Perhaps we are nearing a situation where regardless of optics, sensor or film, mechanical limitations will bring us up against a brick wall which we will only pass by changing how we do things to capture images. Somewhere, I read of the idea of using no shutter at all, but of having exposure made via the trick of switching the sensor on and off for the time required to achieve exposure. Neat, if it can be done; fewer moving parts to go ass over tit. It might come from Canon, seeing how they donīt favour easy MLU ;-)

Just re-read JeffKohnīs last post: is this the same shutter you refer to as an electronic one? I have always assumed the exposing function of an electronic shutter to be exactly the same as a mechanical one: curtains.

Rob C
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: Wayne Fox on April 19, 2009, 04:48:16 pm
Quote from: Peter McLennan
Perhaps it's time to reconsider the mechanical shutter.

Ever observed the "shutter" action in one of the newer Canons ... 50d and 5dMk2?  

There is definitely no mechanical first curtain, and in fact in the correct Live View mode the curtain is open and the mirror up, and exposure begins without any physical movement other than the closing of the diaphragm ... perhaps the ultimate if trying to keep the camera still.

Wouldn't take much to eliminate the 2nd curtain ... perhaps they already have, maybe all it does is protect the sensor.

Title: Mirror Lock-up is a bigger deal than previously thought
Post by: KenS on April 20, 2009, 10:15:29 am
Quote from: Rob C
...
Perhaps the worst case Iīve come across has been with the Pentax 67 ll, where with mirror locked up, on a heavy Gitzo, the shutter has bounced so much that the edges of the frame have been hopeless. Didnīt keep the camera long... a further big loss of money.

Rob C

Why would the edges of the frame suffer from vibration induced blur more than the center?
Was one side of the frame more blurry than the other?
The camera is a rigid body and all parts of the frame are exposed equally.
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: Rob C on April 20, 2009, 03:53:49 pm
Quote from: KenS
Why would the edges of the frame suffer from vibration induced blur more than the center?
Was one side of the frame more blurry than the other?
The camera is a rigid body and all parts of the frame are exposed equally.



Q. Why would the edges of the frame suffer from vibration induced blur more than the centre?

A. In the case of the Pentax, and my work with it, the reason seems, to me at least, to be something to do with the manner in which the two curtains open up and close when making the slit that crosses the film plane. I guess that the initial jarr at the start of the opening of the two blinds is high enough to cause a slight movement in the body and that dies down to negligible levels and then hits again with a bang as the travel is completed.


Q. Was one side of the frame more blurry than the other?

A. Where I noticed the effect to be worse was in a series of landscape shots of a harbour where the masts at the extreme right of the transparency were really badly out of focus. I was shooting with slow speeds and small apertures. I am no longer sure which side of the camera the Pentax blinds started their travel, but if from left to right, and you consider the film to be upside down, it would perhaps indicate that the effect was worse at the start of the exposure than the end of it.


The camera is a rigid body and all parts of the frame are exposed equally.

I agree that itīs a rigid body, the reason I bought the damn thing because the alternative, a Mamiya RB or RZ would be like a sail down at a harbour.  (It matters because I live on an island.) Having already lost my shirt on a Bronica 6x7 also bought because I thought it rigid, prevented me being bitten by that same dog twice.

As for the exposure being equal, thatīs what they all strive for but do not always manage in real life. In fact, thereīs a school of thought that says that it was only with the electronically controlled shutter in the F3 that even Nikon managed that fine trick of perfect exposure across the frame.

Difficult on 36x24mm, probably impossible over 6x7!

Cheers

Rob C
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: Ray on April 20, 2009, 06:57:54 pm
Quote from: JeffKohn
I don't see this as much of an issue for single exposures. You flip the mirror up in anticipation of the shot. I'm not suggesting MLU be used for action photography or BIF's, but for landscapes where you care about the getting the sharpest results possible (often at slowish shutter speeds), MLU becomes important.

With a completely static, unchanging landscape, then using MLU for a single exposure whatever the shutter speed, whether the shot needs MLU or not, is probably no disadvantage (outside of a totally unexpected, sudden change of conditions). However, the characteristics of scenes in general can vary enormously from the two extremes of 'action' photography where MLU is totally inappropriate, to the 'static landscape' where one might always use MLU as a matter of course. I'd prefer in general to be able to see what I'm shooting at the precise moment I press the shutter.

The main disadvantage of using MLU would be when auto-bracketing exposures for merging to HDR. If the longest exposure falls within that danger zone where mirror slap is likely to degrade the result, say 1/60th second or slower, then there'd be circumstances when I'd prefer to increase ISO rather than use MLU. As Peter McLennan mentioned, even movement of clouds can be a problem when merging to HDR.
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: Nick Rains on April 20, 2009, 09:42:49 pm
Quote from: Ray
The main disadvantage of using MLU would be when auto-bracketing exposures for merging to HDR. If the longest exposure falls within that danger zone where mirror slap is likely to degrade the result, say 1/60th second or slower, then there'd be circumstances when I'd prefer to increase ISO rather than use MLU. As Peter McLennan mentioned, even movement of clouds can be a problem when merging to HDR.

Ray, if using the Canon 5D2 (and some others), when you use Live View, 2 sec self timer and Autobracket all together, the camera makes all three exposures in succession without moving the mirror down between shots. It is about a fast as you could possibly make the shots by hand - but no danger of a slight finger pressure movement. I use it a lot and it works a treat.
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: Marlyn on April 21, 2009, 01:35:55 am
Quote from: Ray
Consider also the cumbersome procedure of autobracketing exposure with MLU enabled. It could take up to 10 seconds to take 3 shots even with fairly fast exposures. A lot can happen in 10 seconds.


Using a 1DsIII I use MLU constantly when braketing, and when doing Pano's.    I always select the option "Mirror Lockup, down with Set"

My Settings
- 2 Second timer
- MLU, Down with Set
- 3 (or 5) shot bracket  +/- 1 1/3 generally

When i press the shutter the first time, the Mirror flips up, waits 2 seconds, then takes 3 Shots rapidly (as fast as the High speed auto-fire will take them).  - The mirror STAYS up.
- Move the Head to the next position in the sequence for the pano, press again.    Waits 2 seconds, Shoots the brakets,   rinse, repeat.

Afterwards, either press 'Set' to lower the mirror, or it will do it itself in 30 seconds.


Regards

Mark Farnan
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: Ray on April 21, 2009, 07:33:31 am
Quote from: Nick Rains
Ray, if using the Canon 5D2 (and some others), when you use Live View, 2 sec self timer and Autobracket all together, the camera makes all three exposures in succession without moving the mirror down between shots. It is about a fast as you could possibly make the shots by hand - but no danger of a slight finger pressure movement. I use it a lot and it works a treat.

Nick, I've used the 50D in Live View mode with autobracketing and continuous shooting enabled, and it behaves just like your description of the 5D2. I prefer to use a cable release rather than self timer because I like precise control of the moment, even if it's not always necessary.

However, it seems from JeffKohn's comment that Nikon cameras with Live View do not have this advantage. In Live View mode, the mirror flips down then back up again before the exposure takes place. That seems crazy. Who said Nikon cameras were designed with photographers in mind?  
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: Ray on April 21, 2009, 07:40:59 am
Quote from: Marlyn
Using a 1DsIII I use MLU constantly when braketing, and when doing Pano's.    I always select the option "Mirror Lockup, down with Set"

My Settings
- 2 Second timer
- MLU, Down with Set
- 3 (or 5) shot bracket  +/- 1 1/3 generally

When i press the shutter the first time, the Mirror flips up, waits 2 seconds, then takes 3 Shots rapidly (as fast as the High speed auto-fire will take them).  - The mirror STAYS up.

That's very sensible of Canon to provide such a feature. However, I think this is probably only a feature of the professional series. I've never seen such an option on any of my Canon DSLRs. On the other hand, I'm pretty slack reading instruction manuals   .
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: Dick Roadnight on April 21, 2009, 09:31:45 am
50 Megapixel sensors are not cheap, and if I do not use a tripod (Gitzo Carbon or 10Kg Manfrotto, with geared head) and remote wire release (or flash), the pictures are soft: if you pay three times the price of a D3X, you want better pictures. Even the DSLR has lens (leaf) shutters.

For serious landscapes I will be using a serious mirror-free camera, with leaf shutters and movements: presumably leaf shutters produce less vibration than focal plane?

With higher res and heaver mirrors, you would think that MFDSLRs are much more susceptible to mirror shake.

They used to test cameras and tell you the line pairs per millimetre of the system, but (until now) the quality of digital cameras has been such that "they" have chosen to keep quiet about actual whole system performance.

Of course the Sinar Liquid Crystal shutter is, presumably, vibration-free.

You can watch the subject without looking through the view finder - you can look over the camera, stand where you want the model to look or use the camera remotely, with or without a tethered computer... I don't think they do wire frame view finders for digital cameras, but you do get an optical view finder with the (mirror free, rapid-scan) Seitz 617 digital.
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: BernardLanguillier on April 21, 2009, 08:55:38 pm
Quote from: JeffKohn
I can understand how you might feel that way shooting Canon. In Nikon-land, live-view is no substitute for MLU, because with live-view the camera still drops the mirror down before taking the exposure and then operates as normal.

Indeed, a major issue with Nikon's impementation of Life view.

But either way, Canon does implement MLU as an implicit part of the Live view process and this does confirm the need and value.

Cheers,
Bernard
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: BernardLanguillier on April 21, 2009, 09:42:04 pm
This interesting thread shows that a high resolution sensor makes little sense without a shutter designed to stick to vibrations levels low enough not to affect image quality...

More than ever, the weakest link in the chain is going to define the achievable image quality.

I used to see a clear drop of image quality at low temperatures with my Mamiya ZD and 300 f4.5 combo. Careful analysis showed that the culprit was probably the differential dilatation of the lens mount vs body mount... the colder the temperature, the more play there was between lens and body... to the extend that shutter induced vibration did affect negatively sharpness (I was of course always using MLU).

The day I noticed this was the day I understood that MF manufacturers did probably not have the resources it takes to validate fully complex digital systems.

Either way, larger sensor are more prones to these issues and it clearly shows to me that leaf shutters - either in MF lenses or in Digitars - are the only credible option for MF. Too bad for Mamiya...

Cheers,
Bernard
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: Ray on April 22, 2009, 10:00:15 am
Quote from: BernardLanguillier
This interesting thread shows that a high resolution sensor makes little sense without a shutter designed to stick to vibrations levels low enough not to affect image quality...

More than ever, the weakest link in the chain is going to define the achievable image quality.

I used to see a clear drop of image quality at low temperatures with my Mamiya ZD and 300 f4.5 combo. Careful analysis showed that the culprit was probably the differential dilatation of the lens mount vs body mount... the colder the temperature, the more play there was between lens and body... to the extend that shutter induced vibration did affect negatively sharpness (I was of course always using MLU).

The day I noticed this was the day I understood that MF manufacturers did probably not have the resources it takes to validate fully complex digital systems.

Either way, larger sensor are more prones to these issues and it clearly shows to me that leaf shutters - either in MF lenses or in Digitars - are the only credible option for MF. Too bad for Mamiya...

Cheers,
Bernard

I've never compared the effects of shuuter vibrations at different shutter speeds. Is this an issue, and if so, where's the evidence? It should be easy to test. Take a number of shots at various shutter speeds with MLU enabled, and see if you can detect any difference between, say, 100th sec and 1000th sec.
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: Rob C on April 22, 2009, 10:36:56 am
Quote from: Ray
I've never compared the effects of shuuter vibrations at different shutter speeds. Is this an issue, and if so, where's the evidence? It should be easy to test. Take a number of shots at various shutter speeds with MLU enabled, and see if you can detect any difference between, say, 100th sec and 1000th sec.



Ray, I think the range you mention is too high, in that it is perhaps able to mask movement by itself, by virtue of speed. From a second to about a 100th would be more useful, Iīd have imagined.

I agree with Bernard that focal plane shutters are not a good idea on MF at 6x6 or above, even with film. They were the bug-bear for the early īblads and even Rollei slrs, not to mention the problems I personally encountered with the Pentax 67. I suppose you have to make the decision about what you intend to do with MF. If you are a tripod-based user, then who needs anything above a 500th; if you do, then perhaps other formats are really more suited to your requirements. Yes, lenses with built-in shutters cost more, but then if youīre buying into that system you can probably afford it.

I remember that even when I was using F Nikons for fashion and other model-based stuff outdoors, that I would have welcomed a small selection of shuttered lenses to allow synched flash at perhaps better than 250th, which already meant dropping quality by going for the FM or FM2 though if memory serves, the later F4 allowed the same synch too... Having said that, even with the synch option available with bult-in shutter lenses, there used to be flash manufacturer warnings not to go over a 250th in case of cutting off some of the flash, slow flash being used to create the higher power rating to sell more units etc. etc.

Rob C
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: Luis Argerich on April 22, 2009, 10:47:10 am
Don't know if this helps but I just tested my Canon 40D, in AEB mode with 2 seconds time if I enter live view the mirror goes up, then press the shutter and the 3 exposures are taken without lowering the mirror. Then the mirror stays up so for HDR panos you can just move the camera and take the next 3 Live view even helping compose the overlapping between shots.

I tried handheld at 1/125 1/500 1/30 and the response was so fast that the images almost register perfectly without alignment. I'm surprised.

Having said that I found this thread very interesting and I'm thankful for the information everybody wrote here. I hope my 2 cents help.

Luigi
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: David Sutton on April 22, 2009, 06:01:56 pm
Quote from: Ray
I've never compared the effects of shuuter vibrations at different shutter speeds. Is this an issue, and if so, where's the evidence? It should be easy to test. Take a number of shots at various shutter speeds with MLU enabled, and see if you can detect any difference between, say, 100th sec and 1000th sec.
It probably depends on the camera, tripod and head, but on my 40D with my tripod, shutter vibration is clearly visible at about half a second and is dealt to by putting a bean bag on the camera. I'm guessing, but I think the critical range is about 2 seconds down to about 1/20th.
David
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: photolinia on April 23, 2009, 05:33:14 pm
This discussion is very interesting...  I've been thinking about the ideal purpose for MLU.

Here are my thoughts - based more on engineering background than on photo experience...

Please correct me if I'm wrong

I think the MLU option should only really make sense and be used for longer exposures (typically whenever you would use a tripod -
like sub 1/30 sec).  The mechanical camera vibration caused by the Mirror going up and slapping against the camera chasis is very low frequency and if you have shutter speeds of less than 1/125 sec, most of this vibration will occur after the shot has been taken.

This is particularly true of stuio shots done with strobes, where images are exposed for about 1/1000 sec - the duration of the strobe...

Same thing applies to using a cable release - the spead at which you finger presses and moves the body is very slow and would only
be visible on long exposures...

please correct me if I'm wrong.
-ilya
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: Plekto on April 23, 2009, 07:39:52 pm
OTOH, this might be enough to mangle a bracketed shot.  I'd always use MLU and if possible an IR remote to do bracketed shots.  

Q: how many cameras allow you to keep the mirror locked and do multiple exposures as well as have an IR/etc remote?
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: Guillermo Luijk on April 23, 2009, 08:21:28 pm
With a cheap and light tripod, a remote shutter and setting MLU + 2secs timer in the camera, I _always_ get perfectly aligned indoor shots with my 350D (they match pixel by pixel).

However several people also using remote shutter and MLU on other cameras have reported they get some (minor) misalignment. Can this be just because of the mirror weight?

I have recently purchased a 5D (Mark I), and would love to have perfectly aligned images as well in HDR bracketings. Any reports on what I can expect from bracketing with tripod, remote shutter, and MLU+timer on a 5D?

Regards.

PS: BTW shame on Canon, one of the reasons for not having gone to 5D2 is that is still only does {-2,0,+2} bracketing.
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: bjanes on April 23, 2009, 09:41:30 pm
Quote from: KenS
Why would the edges of the frame suffer from vibration induced blur more than the center?
Was one side of the frame more blurry than the other?
The camera is a rigid body and all parts of the frame are exposed equally.

Camera shake can occur along three axes and can be described as pan, tilt, and roll. Pan and tilt would affect the center as well as the edges, but roll would have a greater effect at the periphery. However, it seems unlikely that significant roll would occur with the camera on a tripod.

Bill
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: Ray on April 24, 2009, 08:27:16 pm
Quote from: GLuijk
I have recently purchased a 5D (Mark I), and would love to have perfectly aligned images as well in HDR bracketings. Any reports on what I can expect from bracketing with tripod, remote shutter, and MLU+timer on a 5D?

Guillermo,
You can expect any movement in the scene to spoil the results   .
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: Guillermo Luijk on April 25, 2009, 08:34:15 am
Quote from: Ray
Guillermo,
You can expect any movement in the scene to spoil the results   .
But movement in the scene is not an issue, the moving area just needs to be masked. My worry is about the heavy mirror included in the 5D (compared to the little 350D).
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: Ray on April 25, 2009, 09:46:03 pm
Quote from: GLuijk
But movement in the scene is not an issue, the moving area just needs to be masked. My worry is about the heavy mirror included in the 5D (compared to the little 350D).

The heavier mirror of the 5D is probably what contributed (in my experiments) to the noticeable image degradation at 1/30th sec on a fairly lightweight travelling tripod (but firmly planted on a tiled floor) compared to the complete lack of image degradation from my 20D on the same tripod at the same shutter speed without MLU being enabled. But I still think it's reasonable to deduce that the unusually noisy mirror-flip (and possibly also shutter) of the 20D probably helps image quality, in the absence of MLU. The lower frequency vibrations are transformed into harmless higher frequencies, which are not good for wildlife shots of course. There's a trade-off.

Such issues really require a lot of time-consuming experimentation under various conditions. I'm all in favour of 'knowing thy equipment', but most of us would rather spend our time just taking photos. It requires a scientific frame of mind to make such careful comparisons to determine at what shutter speeds on a particular camera, on a particular tripod, MLU has the most benefit, if any benifit at all.
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: elf on April 26, 2009, 03:02:19 am
Quote from: Ray
The heavier mirror of the 5D is probably what contributed (in my experiments) to the noticeable image degradation at 1/30th sec on a fairly lightweight travelling tripod (but firmly planted on a tiled floor) compared to the complete lack of image degradation from my 20D on the same tripod at the same shutter speed without MLU being enabled. But I still think it's reasonable to deduce that the unusually noisy mirror-flip (and possibly also shutter) of the 20D probably helps image quality, in the absence of MLU. The lower frequency vibrations are transformed into harmless higher frequencies, which are not good for wildlife shots of course. There's a trade-off.

Such issues really require a lot of time-consuming experimentation under various conditions. I'm all in favour of 'knowing thy equipment', but most of us would rather spend our time just taking photos. It requires a scientific frame of mind to make such careful comparisons to determine at what shutter speeds on a particular camera, on a particular tripod, MLU has the most benefit, if any benifit at all.

Have you tried shooting without using the in-camera shutter to see if it really is the shutter that causes the problem? Shoot in a dark room with a long shutter speed and use room lights to control the exposure time.
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: Ray on April 26, 2009, 05:14:38 am
Quote from: elf
Have you tried shooting without using the in-camera shutter to see if it really is the shutter that causes the problem? Shoot in a dark room with a long shutter speed and use room lights to control the exposure time.

No. I've never done any tests to try and separate mirror slap from shutter vibration. I read years ago that the critical shutter speeds when mirror slap can be a problem are from 2 secs to 1/60th. I've never found a problem outside this range. If the shutter itself also causes a degree of image-degrading vibration, I don't see what can be done about it if it's in the same shutter speed range where mirror slap is also a problem, except use a faster shutter speed.

I was surprised that I couldn't see any difference with the 20D in this range from 2 secs to 1/60th, comparing images with and without MLU enabled. The 5D behaved more typically with the greatest blur at 1/30th without MLU, slightly less at 1/15th and almost none at 1/60th.
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: Rob C on April 26, 2009, 06:27:06 am
Ray, as I think I mentioned before, hard tiles are perhaps worse inducers of vibration than you think. They are totally rigid and incapable of absorbing any vibration and thus dampening it. I think that the same basic notion is at play even when using a strong tripod which fails to have sufficient mass to stop the shakes before they happen. And we havenīt even touched on the kind of feet the tripod may have.

Maybe thatīs the secret behind the old Gitzos which are damn uncomfortable for even healthy people to cart around; perhaps they work better than lighter carbon fibre Gitzos? Who will ever test them, and on which brand of perfect camera? Impossible, of course, all cameras and exposure systems are flawed when movement is required to make that exposure; it is simply a matter of acceptable degree.

Rob C
Title: Mirror Lock-up is a bigger deal than previously thought
Post by: Ray on April 26, 2009, 08:40:20 am
Quote from: Rob C
Ray, as I think I mentioned before, hard tiles are perhaps worse inducers of vibration than you think.

Rob,
But not sufficient to cause any image blur when the 20D, with ultra-light 50/1.8 II, is on the tripod, with or without MLU enabled. One could spend the rest of one's life testing how different cameras behave when attached to different tripods on various surfaces and also when using different lenses which have a different balance and weight. Is it worth the trouble? I just use the 2 sec to 1/60th range as a general guide. I might do some tests with the 50D to see if I can detect any shutter vibration, ie. take a few shots ranging from 2 secs to say 1/200th all with MLU enabled.

All my tripods have rubberised feet by the way.