RiceHigh's Pentax Blog: Sensor-Shifted IS Heats Up the Sensor Much More Than the Video Mode Itself! :-o

Thursday, September 30, 2010

Sensor-Shifted IS Heats Up the Sensor Much More Than the Video Mode Itself! :-o

First, read this advisory note from Sony (reported via here first, here and here subsequently):-

http://support.d-imaging.sony.co.jp/www/dslr/information/news/top_slt-a55a33.html
(in Japanese)

So, we have these information, officially:-

(Source: Sony Japan HQs; Table English via Engadget)

The in-body "Image Stabilization" (aka Shake Reduction or SR in Pentax' term) does actually heat up the sensor seriously, which is far more than the sensor heats up itself during its video recording mode! Whilst this is just a big surprise for this previously unknown technical issue, I have to say it is just a big issue, IMHO!

At 20 Deg. C. room temperature, the video recording time of the A55 is decreased from an original 29 minutes dramatically and drastically down to 9 minutes once the in-body IS is turned on! So, this body IS/SR must be generating much heat and actually such in-body IS/SR system is just so HOOOT!!

This case just let me think again about the usefulness Vs all the shortcomings of all those in-body image stabilisation systems. In fact, it does NOT work well with the video mode, which is now the trend for including this as a *standard* feature in DSLRs or just ILDCs/EVILs. We should note that Sony has not published any advisory note on the high-temperature cut for their NEX cameras. The NEX cameras has IS in-lens anyway and so does Samsung has chosen and opted for the NX line and system to use in-lens IS.

Last but not least, we all know that Pentax does not have any in-lens IS in their system unless the user has to buy a Sigma (OS, which is an in-lens IS system). I don't think Pentax could do the miracle and the Pentax DSLRs do not suffer from the same problem, could they?

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jaad75 · 754 weeks ago

Yes, they could. Pentax SR system is designed differently, so there is the chance it doesn't heat up that much. Plus I would never say "it does not work well in video mode" - actually it works very well and allows to stabilize some prime lenses... BTW, one shoot is usually much shorter than couple of minutes...

4 replies · active less than 1 minute ago

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RiceHigh 110p · 754 weeks ago

What's the "difference"??

I am not saying that SR in video mode does not work, but just want to point out that it works far from perfect, or, should be inferior, in short. Just say that longer focals cannot be effectively stabilised, noise from the SR motors during their operation is more easily recorded and more noticeable. It consumes much (battery) power and energy which is now converted into heat and so on..

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Anu · 754 weeks ago

Longer focal lengths issue is a myth only.

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Jan V. · 753 weeks ago

To my knowledge Pentax SR doesn't make use of any "motors" but solely depends on variable electromagnetic fields!! (see: http://www.pentaximaging.com/pdf/All_Bodies_Shake...

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RiceHigh 110p · 753 weeks ago

So, it's a motor in principle!

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jaad75 · 754 weeks ago

"What's the "difference"?? "
Rice, just take a look at schemes - I'm sure you can easy spot some principal differences...:)

"Just say that longer focals cannot be effectively stabilised"
Yes, they can be stabilised quite effectively, but for filming with longer lens you should use a tripod with really good head anyway.

"noise from the SR motors during their operation is more easily recorded and more noticeable."
A noise from in- lens stabilisation is recorded just as easy - that's another thing why you need an external mic...

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Chris · 754 weeks ago

* The issue you found is with Sony cameras. Due to patent issues, the company's IS designs surely differ a lot.

* Heating causes image noise, probably the reason why you don't like it. Noise in video, however, is FAR less of an issue, because the resolution is so much lower (<2 MP instead of 14 MP in the K-7, a factor of 8 or so), effectively making the pixels bigger, the same effect as going to a larger sensor with the same resolution

* In-body IS, even if less effective as in-lens IS, is IMO preferable, because I love small lenses which do not have built-in IS anyway. Also price-wise: with in-lens IS, you pay the system again with each lens. I would not want that.

C

2 replies · active 754 weeks ago

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Oodini · 754 weeks ago

The Canon 200mm f/2.8 offers IS, and is cheaper than the 200mm Pentax.

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jaad75 · 753 weeks ago

Is it better? BTW, I bought DA*200 cheaper than Canon is listed...:P

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rhermans · 754 weeks ago

Suppose it's cold and you turn on the heating / video mode can you then heat the camera.
I know this sounds stupid, but that is my general idea of video in dslr's.
Also for some shoot the IS is useful, for others I know I had better turned it of (longer focal lengths), I guess that the better high iso noise will do more for those shots that the IS.

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R.E. · 754 weeks ago

Depends on what you want the video for.
If filming scenes for movies this will hardly be an issue.
If you're filming more than that then this will be an issue.
SR must generate heat since it is effectively a linear motor.
Even when off and locked in place it must consume heat to stay there.
Fan cooling is a problem and adding a heat sink is just going to make the thing work harder as it now has to move more mass.

Yes it may be a problem but its just another limitation like anything else. Sometimes you'll reach the limit and sometimes you won't.

1 reply · active less than 1 minute ago

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RiceHigh 110p · 754 weeks ago

In fact, I appreciate the honesty of Sony for publishing factual information for new cameras that they are promoting, which has shown that they are a responsible company, at least.

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Don · 754 weeks ago

lot of metal in a pentax chassis to dissipate the heat on the one hand...
maybe there is a reason Pentax works so well in the cold, on the other hand..