Sigma 17-70 HSM OS + Sony Alpha a580 SteadyShot – A conflict of interest

I have always been fond of the in-camera stabilisation introduced by Minolta and then adopted by Sony and licensed to other manufacturers. On my a350 it was more or less permanently switched on and I generally forgot all about it, whatever lens I happen to put on the camera. It worked well, allowing me to take handheld shots with anything down to 1/10sec.

After my kit was stolen and I looked to replace my “walkabout lens” which was the Sigma 17-70, I realised that the newer model came with two main changes: HSM (Hyper-Sonic Motor, i.e. autofocus motor inside the lens, rather than driven from the camera) and OS (Optical Stabilisation, i.e. stabilisation inside the lens).

HSM has an obvious advantage as it’s quieter and quicker. The older 17-70 was OK in terms of focusing speeds, but nothing to write home about. The new lens is definitely faster and it seems to be hunting less. I’m not sure how it compares on battery consumption, compared to the in-camera motor, but I’m assuming that it should be more economical, as it involves a lot less physical movement and smaller motors. The price you pay of course is that it makes the lens heavier.

OS is less of an obvious story… I quite like the idea on having stabilisation in the lens, as a long lens tends to shake more than the camera body in my hands and in particular at axes that the in-camera stabilisation cannot correct. Lens OS is also visible in the viewfinder so you can actually see that it works and what effect it has.  Sony however already has stabilisation in the body, so where do these two systems sit against each other? Well, a quick hunt on Google and YouTube proved what I was fearing… they do not complement each other. In fact, they totally conflict with each other, making the situation much worse. And from the same tests, it’s clear that in-lens OS has a marginal edge over in-camera stabilisation. So, all things being equal, I should use the in-lens OS.

All things are not equal though. When using the OS on the lens, you have to switch off SteadyShot in the camera. This is a pain! The OS on/off switch on the lens is simple enough. But the a580 (unlike the a350 I had before) does not have a physical button for switching SteadyShot on and off. You need to go the on-screen menu, navigate to the relevant option and switch it on or off. Not only it’s time consuming, but there is also no way of easily spotting that it’s on or off. There is an indicator in the corner of the viewfinder that tells you that camera stabilisation is off, but it’s not obvious when you are concentrating on shooting.

Add on top of that, the aggravation of constantly switching between the two systems when changing lenses (since the 17-70 is my only lens with OS), which I do frequently, and you can see how this becomes impractical. Finally, when shooting on a tripod, you need to remember to switch both off, and to switch one of them back on when you take the camera off the tripod.

While trying it out in the field, I often found myself with either both systems off (not great) or both systems on (absolutely bad idea).

I am aware that I sound like a spoilt brat, moaning, when I have the luxury of two great stabilisation systems to choose from. But what I’m really moaning about is a bad design decision. It’s pretty obvious to me and should also be to Sony engineers, that independent lens manufacturers will not continue to support two manufacturing lines for each lens, one without OS for Sony Alphas and Pentaxes and a separate one with OS for all other cameras. It’s not economically viable. And as OS is becoming more common in the less expensive lens ranges, a mixture of OS and non-OS lenses for the Sony mount was inevitable. And even if it wasn’t obvious, I’m sure that the Sony and Sigma engineers talk to each other! So, deciding to move the SteadyShot switching from a physical switch (as it has been since SteadyShot was introduced on the early digital Minoltas) to a menu option was a BAD design idea! I know it saves money in components and also reduces body size, but at the higher end of the consumer market where the a580 sits, that should not be a primary design driver against usability.

An even better idea would be (and one I’m sure can be introduced through a firmware upgrade) for the camera and automatically switch off the in-camera stabilisation when an OS lens is attached. Even if it’s not possible to detect if the OS in the lens is actually switched on or off (although I don’t see why not…), it could easily be a settings option to disable the in-camera stabilisation when a lens with OS is attached to the camera and then automatically switch it back on when a non-OS lens is attached.

After all, that’s exactly how the camera behaves for HSM focusing.

They say that “you can have too much of a good thing”. Well, this is definitely the case here!


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s