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String trio Australian museum R5 with RF 50mm f1.8 |
When the EOS R5 was announced there was much hype about 8K video and a claimed 8 stop stabiliser effectiveness. Maybe someone at Canon mission central was dreaming in figures of 8.
In due course it was found that although the R5 does indeed shoot 8K video it overheats fairly soon so that feature is rather less capable than originally hoped for.
Canon’s marketing machine also made claims about the in-body-image-stabiliser (IBIS) in the R5 and R6, suggesting an improvement in handholding capability of 8 stops with some lenses.
I recently ran some tests on stabiliser capability, using the RF50mm f1.8, which does not have a stabiliser in the lens and the RF24-105mm f4L (at 50mm) which does have in-lens stabiliser which is supposed to work together with the IBIS for a greater effect than either alone could provide.
I made several series of shots of a test target, hand held using shutter speeds from 1/100 second down to 1 second in 1/3 EV step increments. Several runs had the stabiliser on, several runs had the stabiliser off.
Then I viewed the output frames at 100% on my monitor and rated each as sharp or soft.
I found that with the stabiliser off and careful technique I could produce a sharp picture on 100% of frames at 1/80 second.
With the stabiliser on I got 100% sharp frames down to 1/6 second.
There was some variation from run to run, with the figures quoted being the average values achieved.
With the 24-105mm f4L lens at 50mm I achieved the same numbers.
I also tested an EF 70-300mm f4.5-5.6 mk2 hand held at 300mm on the R5.
With this lens I could consistently get sharp pictures at 1/25 second with the stabiliser on and 1/300 second with the stabiliser off.
Observations
* The old standard one-over-focal-length rule from the good old days of film cameras and low pixel density digital cameras does not always apply. So with a 50mm lens I found I could not get 100% sharp frames at 1/50 second. Even 1/80 second only gave 100% sharp frames with controlled conditions and careful technique. Out and about and grabbing shots quickly I would use at least 1/125 sec and preferably faster.
* I did not find any meaningful difference in stabiliser effectiveness between the 50mm (non-stabilised) lens and the zoom (stabilised) at 50mm. It would appear that at this focal length the IBIS is doing most of the work.
* With both lenses I was able to make sharp pictures on 100% of frames with the stabiliser on at a shutter speed 3.5 EV steps slower than without the stabiliser.
Not 8. Not 5, just 3.5.
That’s not bad, in fact it is in line with stabiliser effectiveness on most modern cameras which I have used recently.
* With the EF 70-300mm lens at 300mm the stabiliser gave me on average about the same 3.5 stop/EV step advantage.
I have no idea whence Canon derived the marketing hype of 8 EV steps/stops.
If the stabiliser system really delivered an 8 EV step advantage it should be possible to get sharp hand held pictures at around 3 seconds at a focal length of 50mm and about 2 seconds at 300mm. But I was unable to achieve anything like that.
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Hurt seal Australian museum |
Shutter shock tests
Mirrorless interchangeable lens cameras with a focal plane shutter can be prone to a phenomenon called “shutter shock” with some lenses at some focal lengths and some shutter speeds. When present the problems manifests as blurring of the photo sometimes with a double image appearance. It is particularly associated with the use of a mechanical shutter to begin and end the exposure.
The R5 has three shutter modes:
1. Mechanical commencement and ending of each exposure.
2. Electronic commencement and mechanical ending, usually called “electronic first curtain shutter” (EFCS).
3. Electronic commencement and ending of each exposure. In this mode the mechanical shutter does not operate and the image capture is silent, apart from beeps, if enabled.
Canon cameras flash a white border around the image preview in the viewfinder to let you know that a picture has been taken.
The shutter of a mirrorless camera is open when the user is previewing the image as it must be to allow the optical information from the lens to reach the sensor.
With Mode 1, mechanical, when the shutter button is pressed the shutter closes then quickly opens again to start the exposure.
It appears that this rapid close/open action can in some cases cause enough disturbance to shake the camera/lens unit and impair image sharpness.
I tested the R5 with the RF 24-105mm f4 L zoom at 105mm using shutter speeds from 1/13 sec to 1/400 sec. There was no problem with sharpness using EFCS or E-Shutter.
With the mechanical shutter I saw a slight but detectable loss of sharpness at 1/100 sec and 1/125 sec.
I also tested the EF 70-300mm f4.5-5.6 Mk2 and found no convincing evidence of shutter shock at any shutter speed with the mechanical shutter.
Discussion
The shutter used in the EOS R and RP (I don’t know if they are the same) makes a hard snappy sound. The shutter in the R5 makes a noticeably softer sound, suggesting that this shutter employs some kind of damping. I don’t know how this is achieved.
Micro four thirds cameras went through this process several years ago when they shifted from using the old style spring driven shutter to the newer type of shutter with electromagnetic damping. This greatly reduces the risk of shutter shock even when the mechanical shutter is used, although the risk is not entirely eliminated in M43 unless EFCS or the E-Shutter are used.
I found at most only minimal evidence of shutter shock with the 24-105 and 70-300mm lenses which I had available for testing on the R5 when using the mechanical shutter and no evidence of any shutter shock problem with EFCS or the E-shutter.