Shutter Shock a myth

Started Jan 1, 2014 | Discussions thread
DavieK Contributing Member • Posts: 705
Re: Shutter Shock is NOT a myth. About the fixes.

I've just done a few tests at 70mm using first the 28-70mm FE OSS, then the Sigma 70-300mm OSon LA-EA3 - three shots handheld with OS, three without, each lens, only twelve shots total but a reasonable test.

Findings - at 1/100th, it doesn't matter whether OSS is on or off on the 28-70mm. The sharpest instance seems to me to be one with OSS off, but the compressed file sizes indicate that one of the OSS examples contains more detail - maybe slight double imaging?

With the 70-300mm I realise that officially you can't have stabilisation ON in the menus (not available with this lens). However, it's equally clear that if you turn it on on the lens, it works.

My shutter speed set was officially 1/100th but I was using A and observing the displayed speed. Some frames were at 1/80th in the final metadata but there was no exposure difference. The Sigma had to be set to f/5, not f/5.6, to get 1/100th but I think the raws were brighter. Raw conversion was ACR, set to Auto levels, all lens correction, NR and sharpening turned off completely; central crop position (differences are due to hand-held aiming). Target is at a slight angle to the camera, closer on right, further away on left, to be sure of some optimum focus within the small area. Actually both the auto and manual focusing methods used seem very accurate indeed.

The pen lines on the artwork are 0.5mm at the finest (dots etc are approx 0.5mm dia) and the shooting distance is 2m. ISO 400 used because that was the best light I could get (500W flood). It's just a quick test but confirms to me that user camers shake around 1/100th (handheld shake induced by the photographer responding to the shutter) is not significant; but also that OSS on the 28-70mm is not very effective, and OS on the Sigma should be avoided.

A7R 28-70mm OSS handheld at 70mm, 1/100th f/5.6, OSS on (open for 100% view)

As above OSS off

A7R Sigma 70-300mm OS handheld at 70mm, 1/100th f/5, OS active on lens switch (visibly so)

As above, OSS off

I'm fairly surprised by the lack of more visible shake all round. It looks as if making three or four exposures with the shutter speed set slightly above the focal length rule (1/80th-1/100th here at 70mm) will in my case produce at least one clean result. Both lenses are also pretty good, the 28-70mm at 70mm wide open is a very sharp lens. There doesn't seem to be much point in using OSS, maybe for longer hand-held shots like 1/8th or so, or for movies. I'ver already found that at 28mm, this lens is sharper with OSS turned off and this probably applies across the focal length range. When doing these shots I was indoors, relaxed and warm. Outdoors, cold, after exertion (e.g. climbing a vantage point - anything which raises the heart rate), in wind, on a rough surface... I'd say halve the shutter then halve it again - 1/500th for a fair chance of sharp images hand held. But that would be with any camera. Too many tech writers like me do their tests indoors in unchallenging conditions!

I certainly won't be using the Sigma OS (pity). I have a Sigma APO Macro 70-300mm which is even sharper and lets me focus closer. The higher ISO settings on the A7R are very good and I'll just aim for shutter speeds in the 1/500th-1/2000th range.

The instruction manual for the A7R/A7 really drives home that the 28-70mm is for the A7 only. I think we'll see a quantum leap in OSS performance as well as lens quality with the 24-70mm CZ, and that the 70-200mm when it arrives may be the only lens in this range with reliable stabilisation on the A7R.


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