Why is ISO cranked up with flash?

Brooke Meyer · 12-21-2014, 07:36 PM

Originally posted by aleonx3

It is the chicken-and-egg scenario, you think that the camera controls the ISO, however, the camera thinks that the flash should take a read on the camera's setting... is it the failure on the flash (egg) or the camera (chicken)? Neither the camera nor the flash knows how you want the final picture looks like.

Which is why you set the camera and flash to manual. You're the only one who knows what you want.

aleonx3 · 12-21-2014, 08:02 PM

Originally posted by Brooke Meyer

Which is why you set the camera and flash to manual. You're the only one who knows what you want.

That's what I meant (almost), camera on manual, flash on manual (or PTTL if you want).... never let the camera choose, the camera can not read your mind of how you want the photo to look like.

Moropo · 12-21-2014, 09:10 PM

Thanks everyone.

What made no sense at all when I created this thread is now perfectly clear. I have learned! Thanks.

I like using Tav mode very much in my daily shooting and I saw no reason why to change that with flash but I now understand. When I'm using flash I will now shoot in M mode.

Question: say I'm shooting in M mode in the camera (K50) and P-TTL in the flash (Metz 50 AF-1) and I want to adjust the intensity of the flash because for example let's say I'm bouncing the flash and the shots are coming out under-exposed. Do I adjust the +/- EV in the camera or in the flash? Is there a difference?

Thanks.

edit: now that I think about it, adjusting the EV in the camera when in M mode makes no sense right? It wouldn't do anything. So in the case that I want more flash power but still remain in P-TTL, I should just adjust +EV in the flash??

Brooke Meyer · 12-21-2014, 10:44 PM

Originally posted by Moropo

Thanks everyone.

What made no sense at all when I created this thread is now perfectly clear. I have learned! Thanks.

I like using Tav mode very much in my daily shooting and I saw no reason why to change that with flash but I now understand. When I'm using flash I will now shoot in M mode.

Question: say I'm shooting in M mode in the camera (K50) and P-TTL in the flash (Metz 50 AF-1) and I want to adjust the intensity of the flash because for example let's say I'm bouncing the flash and the shots are coming out under-exposed. Do I adjust the +/- EV in the camera or in the flash? Is there a difference?

Thanks.

edit: now that I think about it, adjusting the EV in the camera when in M mode makes no sense right? It wouldn't do anything. So in the case that I want more flash power but still remain in P-TTL, I should just adjust +EV in the flash??

Adjust the flash

mikeSF · 12-22-2014, 10:16 AM

Originally posted by Digitalis

...You will never see a studio photographer using AUTO- settings with professional strobes in a studio. ...[/I]

agree 100%

geru2000 · 12-22-2014, 11:25 AM

Originally posted by shaolen

I've experienced this myself and its annoying. They really need to program it better. I feel if flash is being used it should know that it doesn't have to boost the ISO otherwise we wouldn't use the flash

You're making no sense if you've set the camera to auto adjust ISO (TaV) why does it surprise you that after metering the scene it raises the ISO?

If your using PTTL set to TaV then ISO is the only option the camera has to make a proper exposure with or without a flash.[COLOR="Silver"]

---------- Post added 12-22-2014 at 01:34 PM ----------

emalvick · 12-22-2014, 12:03 PM

I seem to recall, thinking back to my pre-digital days, that the primary way a camera adjusted itself for flash was to adjust aperture. It would do this based on the focus distance, typically opening up for the farther away your object is (to let more light in). In TAv mode, the camera would use ISO to achieve the same thing, since you have the aperture fixed.

The principles are still the same coupled with the needs to balance ambient light exposure needs.

For my own needs, I shoot in Manual if the ambient light is important or the flash is just there for fill (kind of the same thing). However, if the flash is the primary lighting for my scene or object, I often go to Tv mode and fix a shutter speed and ISO, letting the camera choose an aperture. If I don't like the aperture selected, I'll manually adjust the ISO to get what I want.

EV for flash and exposure are really again a matter of balancing the fill light vs. ambient light. In manual mode, you just manually adjust EV by what you want. i.e. instead of lining the exposure up for the center (EV=0) adjust it to the right. Flash compensation is really just how much I want the flash to stand out. I typically use a negative flash compensation because I don't want a whole lot of it. I'm usually using it to help things out a bit and not to be a primary light source.

12-22-2014, 11:25 AM	#21
geru2000 Senior Member Join Date: Jan 2009 Location: Watertown, NY Posts: 267	Originally posted by shaolen I've experienced this myself and its annoying. They really need to program it better. I feel if flash is being used it should know that it doesn't have to boost the ISO otherwise we wouldn't use the flash You're making no sense if you've set the camera to auto adjust ISO (TaV) why does it surprise you that after metering the scene it raises the ISO? If your using PTTL set to TaV then ISO is the only option the camera has to make a proper exposure with or without a flash.[COLOR="Silver"] ---------- Post added 12-22-2014 at 01:34 PM ---------- Last edited by geru2000; 12-22-2014 at 11:35 AM.

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12-21-2014, 07:36 PM	#16
Brooke Meyer Guest	Originally posted by aleonx3 It is the chicken-and-egg scenario, you think that the camera controls the ISO, however, the camera thinks that the flash should take a read on the camera's setting... is it the failure on the flash (egg) or the camera (chicken)? Neither the camera nor the flash knows how you want the final picture looks like. Which is why you set the camera and flash to manual. You're the only one who knows what you want.

12-21-2014, 08:02 PM	#17
aleonx3 Veteran Member Join Date: Jul 2007 Location: Brampton, Ontario Photos: Gallery \| Albums Posts: 3,996	Originally posted by Brooke Meyer Which is why you set the camera and flash to manual. You're the only one who knows what you want. That's what I meant (almost), camera on manual, flash on manual (or PTTL if you want).... never let the camera choose, the camera can not read your mind of how you want the photo to look like.

12-21-2014, 09:10 PM	#18
Moropo Senior Member Join Date: Aug 2014 Posts: 131 Original Poster	Thanks everyone. What made no sense at all when I created this thread is now perfectly clear. I have learned! Thanks. I like using Tav mode very much in my daily shooting and I saw no reason why to change that with flash but I now understand. When I'm using flash I will now shoot in M mode. Question: say I'm shooting in M mode in the camera (K50) and P-TTL in the flash (Metz 50 AF-1) and I want to adjust the intensity of the flash because for example let's say I'm bouncing the flash and the shots are coming out under-exposed. Do I adjust the +/- EV in the camera or in the flash? Is there a difference? Thanks. edit: now that I think about it, adjusting the EV in the camera when in M mode makes no sense right? It wouldn't do anything. So in the case that I want more flash power but still remain in P-TTL, I should just adjust +EV in the flash??

12-21-2014, 10:44 PM	#19
Brooke Meyer Guest	Originally posted by Moropo Thanks everyone. What made no sense at all when I created this thread is now perfectly clear. I have learned! Thanks. I like using Tav mode very much in my daily shooting and I saw no reason why to change that with flash but I now understand. When I'm using flash I will now shoot in M mode. Question: say I'm shooting in M mode in the camera (K50) and P-TTL in the flash (Metz 50 AF-1) and I want to adjust the intensity of the flash because for example let's say I'm bouncing the flash and the shots are coming out under-exposed. Do I adjust the +/- EV in the camera or in the flash? Is there a difference? Thanks. edit: now that I think about it, adjusting the EV in the camera when in M mode makes no sense right? It wouldn't do anything. So in the case that I want more flash power but still remain in P-TTL, I should just adjust +EV in the flash?? Adjust the flash

12-22-2014, 10:16 AM	#20
mikeSF Pentaxian Join Date: Jan 2009 Location: East Bay Area, CA Photos: Gallery Posts: 6,620	Originally posted by Digitalis ...You will never see a studio photographer using AUTO- settings with professional strobes in a studio. ...[/I] agree 100%

12-22-2014, 12:03 PM	#22
emalvick Veteran Member Join Date: Feb 2008 Location: Davis, CA Photos: Gallery Posts: 1,642	I seem to recall, thinking back to my pre-digital days, that the primary way a camera adjusted itself for flash was to adjust aperture. It would do this based on the focus distance, typically opening up for the farther away your object is (to let more light in). In TAv mode, the camera would use ISO to achieve the same thing, since you have the aperture fixed. The principles are still the same coupled with the needs to balance ambient light exposure needs. For my own needs, I shoot in Manual if the ambient light is important or the flash is just there for fill (kind of the same thing). However, if the flash is the primary lighting for my scene or object, I often go to Tv mode and fix a shutter speed and ISO, letting the camera choose an aperture. If I don't like the aperture selected, I'll manually adjust the ISO to get what I want. EV for flash and exposure are really again a matter of balancing the fill light vs. ambient light. In manual mode, you just manually adjust EV by what you want. i.e. instead of lining the exposure up for the center (EV=0) adjust it to the right. Flash compensation is really just how much I want the flash to stand out. I typically use a negative flash compensation because I don't want a whole lot of it. I'm usually using it to help things out a bit and not to be a primary light source.