iISO does its thing

The iISO function in the Panasonic G1 (“intelligent ISO”), according to the wretched instruction manual which ships with this otherwise fine camera, does the following: “The ISO sensitivity is adjusted according to the movement of the subject and the brightness”. (Page 79). I use this setting in my default setup for street snaps.

Here the CPU in the camera elected 1/500 second to freeze the running boy and an enlarged view in Lightroom confirms that his shirt is, indeed, tack sharp.

Runner. iISO, Panasonic G1

It’s a two edged sword, however. If you want movement blur, it has to be switched off or, much better, simply set the large mechanical mode dial on top to Shutter Priority, in which case iISO is switched off, though that fact is buried in a footnote in the instruction book. As I wrote earlier, Panny must have had some real live photographers involved in the design of this fine camera. Too bad they weren’t involved in the writing of the manual.

A note on AE lock: You can elect whether the ‘AF/AE Lock’ button on the top rear of the body locks focus, exposure or both, much as you can on the Canon 5D, my other ‘serious’ camera (though the G1 is to the 5D as a Ferrari is to a Mack truck). In both bodies I have set the button to lock exposure only, as focus can be locked with a first pressure on the release button of either.

Canon does this right. The AE lock lasts for some 10 seconds – ample time to recompose and take the snap.

The G1 gets it wrong. You have to keep the button depressed to maintain exposure lock until you press the button. That makes for some strange contortions of the hand.

The alternative in the G1 is to enable ‘AF/AE Lock Hold’, a separate choice in the Custom menu, but they got that completely wrong. Yes, it does lock exposure (and/or focus depending how you set ‘AF/AE Lock’) but the camera’s settings remain locked to your exposure even after the shutter is released. You can only unlock things by again depressing the button on the back of the camera. If you opt for a minimal viewfinder display as I do, you don’t know that your exposure is still locked until you notice a super bright or dim screen when making the next picture. You then scramble to unlock things only to find that your subject has gone ….

What Panny should do is change the firmware so that, with ‘AF/AE Lock Hold’ enabled, the lock is released after the exposure is taken. Let’s hope they change this, as selective exposure reading is a useful tool with dynamic range-challenged digital sensors.