RX10 V Topics

In this issue:

• The One Setting You Need to Change (Youtube video)
• Focusing Issues with the RX10 V
• Examining the Flash Sync Speed

RX10 V: The One Setting You Need to Change

RX10 V Focusing Issues

Several weeks after the camera started shipping (and after my book on the RX10 V came out), some Facebook groups dedicated to that camera started posting test shots which cast doubt about the accuracy of the autofocus at 600mm f/4 using Subject Recognition set to “Animal / Eye”.  Using commercial focusing charts, some (but not all) people were able to demonstrate small inaccuracies, akin to the kind of backfocusing issues that plagued DSLRs in the early days. One of the better youtube videos which demonstrates the issue can be found here. Sony Artesian of Imagery Mark Galer even chimed in with his own treatise on the subject and telling Sony to take this issue seriously.  (My camera checks out just fine.)

Sony has tested units that were sent in for repair and has acknowledged that some do exhibit a problem, and they are working with the engineers in Japan to understand it better.  I suspect a formal announcement on the issue (and hopefully a fix!) will be made by the time the next blog post drops.  Stay tuned.

Flash Sync Speed

So as explained in the sister blog post, I had difficulty shooting with flash at 1/2000th of a second with the RX10 V.  

According to Sony, the flash sync speed for this camera is either 1/2000th of a second at f/8 and smaller (larger number), and 1/1000th of a second at anything larger (smaller number) than f/8.  Why this would be isn't hard to understand.  With a leaf shutter, the light blocking mechanism is actually in the lens, right behind the f/stop blades.  When the f/stop blades are closed down, the shutter doesn't have to travel nearly as much distance to start/stop the exposure than if the f/stop blades were wide open.  

Anyway, as it turns out I've never actually tried overpowering the sun at 1/2000th of a second in the past, but I found out about the problem the hard way while out in the field, doing test shots of photographer Mark Ostow.  The goal was to underexpose the background by about 1.5 stops, and have the flash illuminate the subject via TTL flash metering.  At 1/2000th of a second the flash was so weak that it hardly registered on the subject.  Changing to 1/1000th of a second seemed to fix the problem.  (In fact, the same thing happens with high speed sync also.)

So what's going on?  I did some tests in the studio starting with the Godox TT685:

Same thing.  What if I used a more powerful flash, like the Godox AD200?

Once again, at 1/2000th of a second the subject came out way too dark.

Okay, what if I brought out the big-ass Godox AD200?  Surely the greater power will be able to overcome the light attenuation at 1/2000th, right?

It turns out that the same thing happens with Sony flashes, and also the RX10 IV as well.

So I think I see a general rule developing: Ignore what Sony says.  The fastest practical shutter speed for using flash with these cameras is 1/1000th of a second.

Until next time,

Yours Truly, Gary Friedman