I’ve read on a photographic forum — maybe I should stop reading those things; they’re making a lot of work for me — that the a7II in-body image stabilization (IBIS, aka SteadyShot) improves image quality even with the camera on a tripod. Since the conventional wisdom is to turn off image stabilization when the camera is tripod-mounted, I thought I’d do some testing.
But first, I updated the camera firmware to the version that Sony made available the day before yesterday, which purports to improves IBIS performance.
I don’t know why Sony can’t do the updating like most everybody else.
- Download the firmware
- Copy it to a memory card
- Turn off the camera
- Put the card in the camera
- Turn on the camera
- Format the card in camera
- Take pictures
Instead, the Sony update process goes something like this:
- Download the version of the firmware that’s appropriate for your OS. Is yours 32-bit or 64-bit? Find out.
- Worry about Sony’s history of being hacked and wonder if there’s malware in the updater.
- Find a computer you don’t care much about
- Transfer the updater to it
- Disconnect it from your home network
- Set the camera to be a USB mass storage device
- Turn off the camera
- Take out the memory card.
- Launch the updater
- Find a USB cable. Sony says you have to use the cable that your camera shipped with.
- Look for that cable.
- Decide you couldn’t tell it from any other USB cable
- Grab the nearest USB cable.
- Connect the camera to the sacrificial computer. (Mine’s named Lamb)
- Turn the camera on.
- Click through the updater steps.
- Watch the progress bar as the updater downloads the new firmware.
- Go get coffee.
- Wait some more.
- Shut down the camera.
- Disconnect it.
- Put the USB cable where you can find it for the next update — you know this one works.
- Put the memory card in the camera.
- Turn it on
- Take pictures.
- Restore the sacrificial computer from a backup.
Sony is shooting themselves in the foot on this. They’ve got to test the updater on every supported OS. They’ve go to worry about USB cable and driver compatibility. If they’re smart, they have to do all their updater development on air-gapped computers.
It’s a pain for customers, and it has to be a pain for them.
I employed almost the same test protocol I used a few days ago.
- The camera: the Sony a7II.
- The lens: the Leica 180mm f/3.4 Apo-Telyt-R, with a Novaflex R to E adapter.
- RRS generic plate on camera base.
- The tripod: RRS heavy-duty carbon fiber.
- The head: Arca-Swiss C1.
- Landscape orientation.
- No filter.
- The lighting: a single Fotodiox LED-200WA-56 daylight balanced variable-output flood.
- ISO set to 100, f-stop set to f5.6.
- Focusing manually at f/3.4, using the magnifier. The focus point is a Siemens star on the target.
- Drive set to single
- EFCS on
- Manual exposure mode.
- Self-timer set to 2 seconds
- Steady shot set to off
- Lamp to full, shutter to 1/250 second, make 16 exposures with new focusing for each, turn the light down a stop, make 16 exposures… until you get to 1/30 of a second.
- SteadyShot to on.
- Repeat exposure sequence.
- Develop in Lightroom 5.7.1 with standard settings.
- Crop, export as TIFFs, analyze for horizontal edge and vertical edge MTF50 in Imatest.
- Export the results to Excel, crunch the stats, and graph.
The results, with vibration analysed in both the vertical and horizontal plane:
The bold lines are the average MTF50s. The red ones are with IBIS on, and the blue ones are with it off. The light lines are the mean plus and minus one standard deviation, and give an idea of the statistical spread of the data.
The first thing to notice is how close together all the MTF50 numbers are. The second thing is that, on average, the sharpness is very slightly worse with IBIS on.
OK, so IBIS is at best useless with the self-timer. Does it help any when the shutter is released by hand with no delay? Yeah, I know you’re not supposed to do this. But, if you do, can IBIS save your bacon?
No, it can’t.
So leave IBIS turned off when your camera’s on a tripod.