IBIS test on Sony A6500 and Tamron 70-180/2.8

Started 3 months ago | Discussions thread
Euell Veteran Member • Posts: 4,345
Re: IBIS test on Sony A6500 and Tamron 70-180/2.8

voronspb wrote:

Euell wrote:

Thanks for posting. IBIS, I have read, loses efficiency as focal length increases, which is why Sony includes OSS in its longer FE lenses. So, if your finding estimates 1 EV at 180mm, I wonder whether the A6500 IBIS would yield better results at, say 100mm or 135mm focal length.

In theory - yes. In practice - I see how the magnified EVF image behaves, and I believe that there's something wrong with the lens communication with A6500 camera. At 70 mm in AUTO IBIS mode the amount of erratic movement is noticeably bigger than in Manual mode.

I'll make a video illustrating that.

Well, that's interesting and likely requires a firmware update for the lens. However, that, of course, doesn't change the basics respecting IS and focal length.

One question: is there a difference between APSC and FF when it comes to the amount of compensation required of IBIS for a lens of the same focal length. In other words, does the A6500/6600 IBIS have to work harder to compensate for a 180mm lens than an A7xx?

I don't think so. 24 MP APS-ะก sensor is basically a central part of 54 MP FF sensor. IBIS either keeps the image steady (thus making sharp picture), or it fails, and image twitches, and there's blur.

The only difference is that on tightly packed sensor there's less tolerance to blur amount.

There is at least some authority for the proposition that for APSC you should calculate the minimum handheld shutter speed not at the reciprocal of the focal length, but as the reciprocal of the focal length that would produce the same field of view on a FF sensor. See, e.g., https://improvephotography.com/37091/minimum-shutter-speeds-for-handheld-shooting-the-definitive-answer-to-how-slow-can-you-go/

If that proposition is accurate, then the minimum hand-held shutter speed for a 180mm lens on the A6500 is not 1/180th of a second, but rather 1/270th of a second. And, it would seem there are implications for image stabilization as well.

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