A7R II IBIS effectiveness?

[VirtualRain]

What's the real world effectiveness of IBIS?

 

I've been playing with shutter speed on my A7R II and 55 f/1.8 and find that I get consistent sharp images at 1 stop below 1/FL or 1/30s. But if I go to 1/15s (1/FL-2stops) I get a lot of blurry shots. My motor skills are probably typical after a double espresso So is just one stop of stabilization all you can expect from IBIS? That seems rather lame but with a 42Mpix sensor I guess it's pretty good.

 

What's the consensus here on how many stops under 1/FL you can shoot consistently sharp?

[VirtualRain]

I did some rigorous testing today... Here is what I found...

 

(Note all stops are relative to 1/FL or 1/60th in this case as all testing was conducted at FL~55mm)

 

Without any stabilization (FE 55 and stabilization off): only 30-50% keepers at -1stop

 

With IBIS only (FE 55 with stabilization on): 30% keepers at -3stops, 90% keepers at -2 stops, and 100% at -1stop

 

Using my 24-240 at 55mm with OSS it achieved the same result as IBIS only with the FE 55mm. Hence it appears that with lens OSS+IBIS offers no added stabilization vs IBIS and no OSS.

[Guest all8]

Well then, based on that, Its probably your technique which is at fault.

[VirtualRain]

Well then, based on that, Its probably your technique which is at fault.

At fault? I'm not sure what you mean.

 

I'm getting pretty good keeper rate (e.g. 90%) at 2 stops lower shutter speed than the conventional 1/FL indicating that IBIS is providing 2 stops of compensation which seems reasonable, especially with a 42Mpix sensor.

 

What is the advertised benefit of IBIS? What are other people seeing in real-world shooting?

 

Are you saying my results are very different from what is expected? And my handheld shooting technique flawed?

[Guest all8]

I have no idea. 1/60, 1/30, 1/15, 1/8 - thats -3 stops right? 1/8, I would struggle with that. Well, the 1/FL rule was a guideline ... ability and equipment were what produced a sharp image.

 

Once you get to 1/8 the subject must be static enough that a tripod starts to be more interesting, since you can expose for seconds and lower ISO to Base level.

[Guest all8]

You can also read the Spec of the CIPA IBIS Rating System here:

 

http://www.cipa.jp/image-stabilization/documents_e/DC-X011-2014_E.pdf

 

that Test Method is what the manufactures base their various claims on.

[Golem]

At fault? I'm not sure what you mean.

 

.................... 

  

 my handheld shooting technique flawed?

    

Undoubtedly. Acoarst that applies to all of us humans.

We are not tripods ! So it only boils down to a question

of degree, of how sorely flawed. And for most humans,

practice has a positive effect. 

  

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I am well practiced and can be so gentle and gradual

on the shutter release that sometimes I get two frames

even tho the camera is set to single. IOW sometimes

my motion actually "hovers" right at the actuation point

in the button travel. But this is for static subjects only.

Obviously, such care concerning actuation precludes

any attempt to choose the exact moment of release.  

   

This is with a 350mm @ f/5.6 from about 4 ft away.  

IIRC speed was about 1/15. Being seated I was able

to sit cross legged and braced the lens on my knee.  

The foam pad is about 1cm thick, and the image is

cropped, so the effective FL is more like 500mm. It's

not technically 100% but is still an amazing testament

to IBIS when used with care.

 

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[pflapf]

I have no idea. 1/60, 1/30, 1/15, 1/8 - thats -3 stops right? 1/8, I would struggle with that. Well, the 1/FL rule was a guideline ... ability and equipment were what produced a sharp image.

 

Once you get to 1/8 the subject must be static enough that a tripod starts to be more interesting, since you can expose for seconds and lower ISO to Base level.

I can't or don't to take a tripod with me all the time, particularly when on holiday. Being at the beach in the evening or night is wonderful but most probably I have to carry my kid back and not the tripod. ;-)

Low-light portraits is a use case as well. Most humans are able to stand still for about 1/30s while my 85mm would like to have 1/100s.

 

I've been able to shoot the 85mm Batis with 1/4s crisp sharp. I need 3 to 4 attempts and preferably not too much wind. But otherwise it's fine.

[Golem]

..................

 

Low-light portraits is a use case as well.

Most humans are able to stand still for about

1/30s while my 85mm would like to have 1/100s.

 

..................

No. The 85 "wants" 1/30. Thaz the whole

reason it exists. It's only slightly longer than a

normal both physically and optically. The rule

for handheld speeds is NOT 1/FL. It's half that.

 

IOW a 50 is good down to 1/25 for most users.

The 85 requires just a little extra practice to

be used at the same speeds as the 50.

 

There is a "rule" of 1/FL, but it's not a guide

for minimum speed. It's a guide for relatively

careless users.