ISO Consistency from G9 to G10 - DPChallenge Forums

Canon RF 24-70mm f/2.8 L IS

02/23/2009 06:50:20 PM · #1

My bro-in-law called me with a problem he's having. He replaced his Canon G9 with a G10 (the G9 was dropped).

He uses it to shoot patients faces (basically headshots) before and after surgery, so he has a nice light set up, and uses a tripod etc. His staff actually takes the pictures, but basically we had the G9 set to Aperture priority, ISO 200, and with the high power lights he had, he was getting good exposures at a decent shutter speed.

He just got the new G10, and in Av mode, in the same setup, he is getting shutter speeds .3 seconds and over. That's of course, not good enough.

Since ISO settings are standardized, shouldn't the new camera produce approximately the same shutter speed given a fixed ISO and Aperture (and a constant lighting setup)? I don't understand how these cameras could produce such variations in the meter reading. (He lives far from me, so this information is all third hand, by phone, so there can be innacuracies above.)

I'm wondering if his camera is defective.

Any ideas? Any Canon G10 owners having problems with sensitivity or meter readings?

Message edited by author 2009-02-23 22:07:23.

kirbic

Canon EOS R5

02/23/2009 07:03:24 PM · #2

Sounds like it's metering for the ambient light... are the lights hot lights or strobes? If strobes, are they firing, I'm wondering are they firing at the correct time?

02/23/2009 07:10:43 PM · #3

Originally posted by kirbic:

Sounds like it's metering for the ambient light... are the lights hot lights or strobes? If strobes, are they firing, I'm wondering are they firing at the correct time?

They're hot lights, I believe. (I was there once.)

02/23/2009 07:36:49 PM · #4

any idea what he has the aperture set at on the G10?

02/23/2009 08:46:19 PM · #5

Originally posted by Bugzeye:

any idea what he has the aperture set at on the G10?

F4 I think he said; maybe F5.6 (or something in between if it supports it.)

He also has it set to ISO 200.

But the real issue is: he has the two set the same. Shouldn't the shutter speed set (automatically) be similar, or no more than 1 stop different?

Message edited by author 2009-02-23 20:47:41.

02/23/2009 09:27:15 PM · #6

So, I just took both my G9 (well, it's my wife's now :-) and G10 and pointed them at the Nikon D3 poster on my wall :-)

ISO 200, Aperture Priority set to F4, no flash, both exposed at 1/5th...

Couple things to note: when I neglected to turn the on-camera flash off, the shutter speed was 1/60th..... So, if he had the on camera flash contributing in one situation, not in the other--big difference, and that might explain it.

Also, the two have different focal length zooms, so when zooming to approximately the same composition filling the frame, the focal lengths will be slightly different. The G10 is wider angle, so a bit of zoom is required. (I started this little test wide open at f2.8 on the G9, but found that when I zoomed with the G10 to approximate the composition, it's minimum aperture shifted up from 2.8 to 3.2, so I started over with f4). Not enough of a difference all on its own, but could be contributing.....

The flash seems a likely culprit to me. If he had it on in the original set up with the G9, even though he may not have noticed it, then turned it off with the G10, that could explain the difference pretty quickly.

G9 version:

G10 Version:

both are a bit soft, as I was handholding at 1/5th

Message edited by author 2009-02-23 21:51:22.

02/23/2009 09:28:04 PM · #7

I think it would depend a little bit on how much zoom he is using. I just got the G10 a couple of days ago to replace a A590IS that was not cutting the cake for me. So I know very little about it at this stage. There are alot of bells and whistles on the G10 that can be tweaked or turned off. So there could be a host of different things causing the difference in shutter speeds between the two cameras.

So far I gotta say I love the G10. I am not going to jump off the Nikon Train but I certainly have upgraded my respect for Canon.

ETA gotta love the irony of everyone in this thread being Nikon guys talking about Canon.

except for Fritz however he has a Nikon in collection as well.

Originally posted by nshapiro:

Originally posted by Bugzeye:
any idea what he has the aperture set at on the G10?

F4 I think he said; maybe F5.6 (or something in between if it supports it.)

He also has it set to ISO 200.

But the real issue is: he has the two set the same. Shouldn't the shutter speed set (automatically) be similar, or no more than 1 stop different?

Message edited by author 2009-02-23 21:31:34.

02/23/2009 09:47:36 PM · #8

I think I figured it out: have him check his metering selection: Evaluative, Center Weighted, or Spot could make a big difference. In the pics I took as examples, I had both at evaluative. Given the subject in these, switching to spot made over a full stop difference....

I added the pictures to my earlier post for reference....

02/23/2009 09:49:48 PM · #9

I doubt he had the flash on, and in any case, it doesn't make sense that with two powerful studio lights he'd need it to shoot at least 1/30 at F4 or F5.6 at ISO 200.

Thanks for the test chromeydome; I think that suggests without some anomaly there's something wrong with the new camera.

There's another possibility I've been thinking of. Perhaps the new camera is somehow spot meter reading? And it's reading the background rather than the person...e.g., maybe a setting is wrong.

Thanks for the help everyone!

02/23/2009 09:53:58 PM · #10

Originally posted by nshapiro:

We posted nearly simultaneously--I agree that metering mode is much more likely: on the g10, the button at the 1 oclock position above the "wheel" on the back will, in Av mode, switch between aperture control and metering mode. When metering mode is selected, 3 choices appear on the lcd, and the scroll wheel gets you thru them.

02/23/2009 09:58:36 PM · #11

Originally posted by Bugzeye:

So far I gotta say I love the G10. I am not going to jump off the Nikon Train but I certainly have upgraded my respect for Canon.

ETA gotta love the irony of everyone in this thread being Nikon guys talking about Canon.

Yup! I think Canon's point and shoots reign supreme, and the G9/G10's are awesome cameras. But I do love my Nikon dslrs..... no plans to switch. :-)

02/23/2009 09:59:25 PM · #12

i just goofed around with those settings and got about the same results ,a full stop difference. Im a betting man on this one and would bet that the camera is fine and the settings just need to be adjusted. I am trying to remember what the default setting was before I went into the menu and changed everything. I believe I changed it to center. ETA. After I let it bug me for awhile I did a factory reset, default setting was Evaluative

Originally posted by chromeydome:

Message edited by author 2009-02-24 01:42:39.

02/23/2009 10:35:26 PM · #13

Thanks! That seems to be the best explanation, especially if it doesn't matter whether spot is in the center or not. I just wrote him an email, and we'll see what he comes up with.

02/24/2009 11:27:27 PM · #14

My Brother in law reports tonight that he read the manual, went through all the settings to make sure they were the same on the G9 and G10, and the problem is resolved.

He didn't know specifically what did it, but obviously, some settings were off.

Thanks again, everyone.

02/24/2009 11:54:22 PM · #15

Thats cool. Glad it wasn't a problem with the camera.