Mirror Lockup Is a Conspiracy (Sort of)

Mirror Lockup Test
A shot of our setup for one of the tests we did. I'm shooting tethered into Lightroom with a Tripad holding the laptop and shooting at a focus target and paper with text so sharpness is easily determined.

I often hear photographers preaching the gospel of mirror lockup as a way to achieve sharper images.  In fact, when shooting at a popular landscape photography destination like Yellowstone, you'll often hear most of the cameras using mirror lockup.

Mirror lockup is a function available in most cameras (though not some of the entry level Nikons and not in most Sony cameras due to the pelicle mirror).  Mirror lockup makes the mirror flip up for a moment before you activate the shutter.  The idea is that the vibrations caused by the fast-flipping mirror can cause sharpness problems.  Generally, mirror lockup is used by landscape photographers and macro photographers who are shooting from a tripod.

So, in theory, mirror lockup makes sense.  It stands to reason that getting rid of vibration would cause sharper pictures–especially for longer exposures.  But I've always felt like it was a conspiracy of the camera manufacturers.  I think they got together in some high rise in Japan and decided to put one feature in our cameras that was nothing more than a placebo, and they've been laughing about it ever since.  “What fools!” they say, as we tout the placebo and use it so we can feel like our photos are sharper than the blockhead next to us who hasn't yet discovered it.

I'm not the only photographer who has doubted the practical effect of mirror lockup (MLU).  A previous test was done that is specific to macro photography (and the result was the same as mine). I have periodically used mirror lockup, but to be honest, I've never really seen the difference.  I just did what everyone else told me to do.

Mirror lockup has been in cameras for many decades.  In fact, some early SLR wide-angle lenses couldn't mount without the mirror locked up.  Mirror lockup made more sense in the film days when the mirror flopped with greater force.  Since then, efforts were put in the design of the mirror to reduce the vibrations it caused.

The Mirror Lockup Test

This week, I put it to the test.  I shot comparison photos for hours on different camera systems, different lenses, different focal lengths, different apertures, different tripods, different distances, and every imaginable shutter speed.  I wanted to know once and for all if it was a useful feature, or if the Japanese high rise meeting was real.

I created a spreadsheet and catalogued the camera settings, distance, and many other relevant data points for each of the shots so that no human error could impact the results.  After the test was finished, I took the photos to Dustin and had him look at each of the pictures to guage sharpness in a blind test without telling him which shot was and wasn't shot with mirror lockup.

All photos were shot using contrast detection focus with a perfectly well-lit focusing target.  Sharpness on the unprocessed photos was judged at 100% view.

The Results of the Mirror Lock-up Test

Mirror Lockup makes absolutely zero visible difference in the sharpness of the photo IF you shoot from a rock solid tripod and ballhead.  Period.

When the test was performed on my favorite tripod, there was no difference in the sharpness of the photos at all.  However, when we tested lighter and cheaper tripods, poor quality mounts, or if the ballhead was not tightened down properly, mirror lockup made an obvious and profound difference.

First lesson learned from this test: If you use a high quality tripod, mirror lockup makes no difference at all.  When I say “no difference” I mean the photos look identical to my eye.  This was tested dozens of times at shutter speeds from 30 seconds to 1/2000th and EVERY shutter speed in between.

Mirror lockup test
Using a rock solid tripod and head, there is no difference in sharpness. This photo shot with a Nikon 70-200 f/2.8 at 190mm at 1/40 shutter speed, using a cable release to trip the shutter.

However, I also tested cheaper camera bases and heads.  Second lesson learned from this test: On unsteady or cheap tripods and heads, mirror lockup made a profound difference but the difference was ONLY noticeable between 1/80th down to 3″ shutter speeds.  The shutter speed most prone to vibration problems was 1/40th on the cameras I tested.  All other shutter speeds showed no difference in sharpness with or without mirror lockup.  At fast shutter speeds, mirror lockup makes no real difference because there simply isn't much time for the vibration to impact the photo.  At longer shutter speeds such as those used for night photography, the vibration only occurs during a tiny fraction of the overall exposure time, so it isn't noticed.

For advanced photographers who use extremely heavy (and expensive) lenses that have a mount on the bottom of the lens, you should know that in my testing of the 70-200mm f/2.8 lens, I saw that mounting the lens to the ballhead proved to be a very unstable platform.  With the lens mounted to the ballhead, MLU made a profound difference at 1/40, but when I mounted the camera to the ballhead with the same settings, there was no difference between the MLU and non-MLU photos.  Obviously, the danger in doing this is that the weight of the lens pulls on the lens mount and destroys your camera… so I don't recommend it at all.  I only did this for testing.

A 100% crop of photos taken with and without MLU.
This test is shot with the same settings as the example above, but this time from a cheap tripod. The difference between MLU and no MLU is dramatic!


I'm done with mirror lockup.  It is one more setting I can ignore when in a shooting situation.  To me, it's important to pare down my gear, settings, and everything else during a shoot so that I can focus on creativity and lighting.  It is important to remember that using mirror lockup certainly will not hurt the sharpness of your pictures, but I find that being overly burdened with too many camera settings negatively impacts my ability to make a great photo.

However, if you don't yet have a professional tripod and ballhead (click here to see my good, better, and best tripod and ballhead recommendations), then MLU is one setting you should pay attention to when using shutter speeds between 1/80 and 3 seconds.

As mentioned previously, advanced photographers should know that mirror lockup does make a difference when shooting extremely heavy lenses where the lens is mounted to the ballhead instead of the camera.

34 thoughts on “Mirror Lockup Is a Conspiracy (Sort of)”

  1. Hah! Glad I found this, I was planning on using this during my outdoors trip in the next few days. I guess I’ll still try it just to do a self test on MLU. Thanks for the info. I guess for those very lightweight flimsy tripod’s it’s a must.

    1. Mirror lock up is a MUST in astrophotography, or when using long focal length lenses.
      Even when using very sturdy EQ6 equatorial mount, I could not get proper Moon eclipse photos (with MTO 1000mm lens) without MLU functionality – images were always smudged in up-down direction.

  2. The mirror has to be out of the way before the shutter opens. Your test confirms what I always thought. Shoot SLT’s now. Love them.

  3. James R. Kyle

    Sorry I beg to differ….

    I make use of “LIVE-VIEW” on the Canon 5D MarkII and 60D…. As in “Low-Light” the auto-focus gives me LESS then Best focus in these Low Light conditions with a variety of lenses. (i.e.= the 24-105mm and the 70-200… ON a TRIPOD.

    I take the Live-View and use it as I would a “View Camera” – (i.e.= Ansco 8X10 and or a Crown Graphic 4X5)….

    Using this procedure – I first use auto-focus to set the image… Second, I turn on the Live-View and increase the magnification to 10X. Third, I often use a “loop” to even get MORE magnification on the LCD .. Fourth, I often must re-focus to get the image the sharpest that the lens will deliver.. Fifth, I set the f-stops to what I wish to achieve in the final Print. Sixth, As I Use Aperture Priority, I am not concerned about the shutter speed (that is UNLESS I am in Total manual mode.) and finally I open the shutter and capture the Image in RAW.

    This works well foe me .. Others may have their own methods.

  4. Great test ! I’m just curious to know what you declare a “rock solid tripod” and a “cheap tripod” to get these results. As tripods can go from 15$ up to thousands of dollars. It’d be nice to see some images or links to the tripods used, mainly the cheap tripod.

  5. @James R. Kyle – Thanks for your very detailed explanation of how you shoot, but you didn’t say what you “beg to differ” about.

  6. @Sean – I linked twice in the article to my tripod recommendations. I used the Induro AT-313 for the solid tripod.

  7. @James R. Kyle – Sir, did you read the article? This article is about Mirror Lock Up and the effectiveness or ineffectiveness thereof. Did you mean to comment in a different blog on another open tab?

    Jim, great article! I’ve always wondered if MLU is just hype that camera manufacturers “invented”. It makes complete sense that it is only affected at certain shutter speeds and with an unstable tripod. I think you’ve finally convinced me to purchase a new Induro tripod! Thanks for the article and the painstaking test you did.

  8. I’d be interested to know which tripods were used for the cheap and pro comparison. How cheap was cheap and how expensive was pro? Or what are the qualities of each.

    I read your write up about tripods and that is what makes me wonder. I have a manfrotto 3001 and just wondering which side of the mirror lock up fence that would leave me on.

  9. I am glad you added ” Mirror lockup made more sense in the film days when the mirror flopped with greater force.” I still use occasionally my Pentax 6×7 and the mirror slap on that lovely beast scares mammals and small children…

    On a serious note I have noticed that there is far less vibration transmission when using a carbon fibre tripod as opposed to a aluminium model!

  10. James Kyle said he “begs to differ,” but didn’t say why. I agree with James comment and this is why I beg to differ.

    You said that you felt the camera manufactures got together in a high rise and came up with MLU and then have been laughing at us ever since.

    In your summary you listed several times MLU could be, should be used. There have bee several times I have been in situations where my tripod wasn’t with me. To try and get the shot I wanted in low light I had to crank up the ISO to get above 1/60th shutter speed to get a clear shot. Now, after reading your article, I am placing MLU into my bag of tricks. Next time I am caught in a low light situation without my tripod, I will remember to use it first to avoid increasing the ISO.

    With much practice I can get clear, sharp, images down to 1/30th, sometimes lower, with just hand holding the camera. Now if I use MLU I can be even more confident in those situations.

    Great article with lots of information. Yet next time you may want to select the title of the article a little more carefully.

  11. If you’re using a non-IS 70-200mm f/4 L, MLU comes in handy at shutter speeds between about 1/3 and 1/20 of a second. I do see a difference on my photos when I use it and when I don’t under those conditions.

    Also, I’m a little confused by your method. You said that attaching the lens to the tripod caused more camera shake. I’m assuming you did this with a lens collar? I would think just the opposite would be true, although I haven’t tried it myself. Lens collars are supposed to make your camera more stable with lenses such as the 70-200.

  12. It’s seems to be almost an epidemic nowadays to write a title that doesn’t match the content of the article (often probably to lure in more readers). This test actually tells that MLU is often a very useful feature. So what’s that about a conspiracy? It’s not bad to have something funny in an article, but I think the funny shouldn’t undermine the subject matter.

    And it does matter: people surprisingly often go with the title when the title and text contradict each other, even when the title is obviously wrong.

    Anyway, the results of the test are interensting and useful. Thanks!

  13. Jim, you forget to consider the important option of a tripod with levelling base.

    Consider all those photographers (few?) that do not arrive on the site, they go down from a car and begin to shoot, but that make long and exhausting mountain hikes and who can not, or do not want, to go with a too heavy rock solid tripod along with a Sherpa which leads the rest of the equipment.

    You do not consider that not always there is a stable terrain as a rock under the feet of the tripod, but also soft ground and grass and that completely eliminates the stability of “rock solid” tripod that will vibrate whenever a fucking mirror moves. Sometimes even the shutter curtains will create enough vibration to create blur, visible also with medium focal lengths.

    For years now, in natural environments, the landscape-man can shoot with live view instead of the mirror-up: it is a viable alternative and often equivalent, if not often better for the quick operational times, safety & faster.

    You do not consider those photographers (just me on the face of the Earth? No!) who do not use a good and very stable ballhead (such as one of those of RRS that i have and remain in my studio), but instead a complex multi-articulated panoramic head to take many shots, even on multiple layers that allow to set the optic in his nodal point, for a perfect post processing stitching.

    Here we do not need a ballhead, but a tripod with a levelling system, better if is built in, otherwise, added after, and something like “Ultimate-Pro Omni-Pivot” of California RRS, or as the Chinese PANO -3 by Sunwayfoto, or other heavier or lighter devices.

    But all these added arms and articulations, even if well designed and made, amplify the vibrations, and the “mirror-up”, or “live-view on”, plus the remote control and/or delayed shutter remain a must if we cannot shot inside the safety shutter time range, that can be a variable with wide limits!

    Under these circumstances, even only one blurred shot can ruin the whole panoramic and usually you could realize it too late and cannot go back and ciak again.

    The risk of blur could be always present as a trap.
    If you are in a comfortable room of a study, in a laboratory, under comfortable circumstances with stable temperature and humidity, without wind, with the flat stable ground and not crumbly or slanted, you are not tired so everything seems easier and obvious, but is not always so.
    Also me, I am using and have used many brands, reflex and mirrorless (but still not a Sony Pellix).

    I mention an example from my recent experience.

    Combined of the “quiet” Olympus OM-D E-M5 with the light Canon FD 500mm f/8.
    A mirrorless … but still with curtains!

    If I take pictures with the pano multi row system with portrait orientation, on a stable tripod (I use Gitzo, Induro, Cullmann, carbon, magnesite, alluminium, various versions…) in the about 3 sec … 1/200 time exposure range, I could obtain all shots blurred or very blurred. But instead, I could obtain also no blur, …say, perhaps crisp enought, using 2 different arrangements.

    Under these conditions, with this system, which is best for the best stability?
    Mount this camera-lens couple on the arm of Ultimate Omni-Pivot:
    on the camera with or without its specific plate made ​​by RRS (BOEM5) or instead
    on the solid tripod mount of the the “big” light Canon 500/8?

    Of course, to have the best apparent static stability, with this combine, mounting on the lens give the best result because is pretty close to the gravity center of couple camera-lens.

    But is this solution the best providing no-blurred images?
    Yes or no?
    It’s like having a well-mounted gate, with the counterweights.
    Moves easily with low effort.

    Also the lightweight, seemingly innocuous, curtains flapping quickly, swing axis of balance the whole system!
    You cannot see easly the vibration with your naked eyes.

    But if, on the contrary, you mount this couple from the camera side, with or without his plate, so that all is front unbalanced from the weight of the lens, and the movement of the shutter curtain is not magnified by the lever effect, this does not produce a perceptible vibration that degrades the details, at least not with a 16Mp sensor.

    And here there isn’t a moving mirror, but those nice, light, gentle fucking curtains on the front of the sensor! 🙂

  14. If I’m using the Live View feature on my 5d2, the mirror is already up. So using MLU is pretty automatic if doing it that way and not that much of a pain to use. Plus the histogram can be shown and if I set it to auto bracket, I usually just use the timer to trip the shutter and it automatically takes 3 exposures.

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