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#1 Jasoncassanova

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Posted 31 March 2011 - 10:20 PM

well usually we set our ISO at 100 as standard, although I have a question, what is i have two 8 in. arms holding my DS 160 Ikelite strobe and I have set it to TTL. Since my light is kinda strong and I'm still new in taking pics, the pic kinda comes out brightly lit, would it be better if i'd take it a notch down to 80 ISO? I know I can still do adjustments on Aperture and Shutter Speed, but I'd like to know if putting my ISO to 80 would make a better result?

#2 Damo

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Posted 01 April 2011 - 12:14 AM

Hi ya Jason,

Well from the little bit I know- the general iso standard for underwater pics is 100 or 200.
If you have lower ISO values eg.from ISO 100 to ISO 80, and keeping all your other settings constant, yes the light should 'back off' so to speak in your image, and when you make a print, your 'grain saturation' of colours etc. should be even better!
You could also reduce your aperture at iso 100, back off on the strobes etc....there are so many combinations you can go with!

Are you finding this is 'over bright' phenomenon in your macro or in wide angle shots?
I would imagine this tactic of yours would work better for macro, because you are closer to your subject so your strobes will have more powerful effect.
If you were shooting wide angle you might actually find your pictures too underexposed with iso 80- so you may have to switch to diffent iso eg. iso 200.

So in theory, to answer your question- yes- however- this all depends on what you are shooting at the time, ambient light conditions, subject location, sizeof subject, size of scene, visibility of water etc etc etc

Its all down to experimentation and learning...and every shot condition will have a different setting.
Changing the ISO down is only one way of making your shots better

Happy learning

ps. I dont have a facility to shoot TTL on my camera at the moment- so I cant help you there. For strobes I just mess around with strobe angles, strobe setting, and of course, a combination of ISO, Aperture, and shutter speed.

Edited by Damo, 01 April 2011 - 12:17 AM.

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#3 Scubamoose

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Posted 01 April 2011 - 01:04 AM

Hi Jason!

Ever considered choosing strobe power manually?

Cheers
Karel
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#4 Jasoncassanova

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Posted 01 April 2011 - 03:37 AM

Hi ya Jason,

Well from the little bit I know- the general iso standard for underwater pics is 100 or 200.
If you have lower ISO values eg.from ISO 100 to ISO 80, and keeping all your other settings constant, yes the light should 'back off' so to speak in your image, and when you make a print, your 'grain saturation' of colours etc. should be even better!
You could also reduce your aperture at iso 100, back off on the strobes etc....there are so many combinations you can go with!

Are you finding this is 'over bright' phenomenon in your macro or in wide angle shots?
I would imagine this tactic of yours would work better for macro, because you are closer to your subject so your strobes will have more powerful effect.
If you were shooting wide angle you might actually find your pictures too underexposed with iso 80- so you may have to switch to diffent iso eg. iso 200.

So in theory, to answer your question- yes- however- this all depends on what you are shooting at the time, ambient light conditions, subject location, sizeof subject, size of scene, visibility of water etc etc etc

Its all down to experimentation and learning...and every shot condition will have a different setting.
Changing the ISO down is only one way of making your shots better

Happy learning

ps. I dont have a facility to shoot TTL on my camera at the moment- so I cant help you there. For strobes I just mess around with strobe angles, strobe setting, and of course, a combination of ISO, Aperture, and shutter speed.


Damo,


Well you actually nailed my inquiry, this over bright phenomenon happens when i shoot macro, the DS 160 is a powerful strobe at TTL with just less than 16 in. away from the subject, it brightens the subject a lot than expected. so i was wondering if i can't adjust my strobes any farther and would want to have a result in a good combination of aperture and shutter speed, i was hoping that i'd rather change the iso setting if it was possible. since i'm just starting, i'm shooting during the day and mostly around 10ft - 20ft. depths. i agree that lowering the ISO on a wide angle shot would make it underexposed.

thanks.

Jason.

Edited by Jasoncassanova, 01 April 2011 - 03:45 AM.


#5 Jasoncassanova

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Posted 01 April 2011 - 03:54 AM

Hi Jason!

Ever considered choosing strobe power manually?

Cheers
Karel


Karel,


well since i'm just new, my friend told me to practice with TTL first before i start with manual.



Jason.

#6 Scubamoose

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Posted 01 April 2011 - 07:43 AM

Karel,

well since i'm just new, my friend told me to practice with TTL first before i start with manual.

Jason.


I see You'r point. Then again many start with manual and use TTL only occasionally. Specially in macro You can achive interesting lighting (shadows etc) with two strobes on different power settings. A long talk in short - start trying manual :) The sooner the better. IMHO TTL gives often boring even lighting ;)

Cheers
Karel
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#7 Cerianthus

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Posted 01 April 2011 - 07:47 AM

I am sure you are aware that strobe light can be controlled with strobe power (either manually or by TTL), , distance to subject and aperture. The answers up till now seem to forget the aperture.

For Macro, to get good depth of field (if there is enough light) you can use small apertures (high number such as f16). What are you using normally : i have other ikelite strobes, but if the aperture is too large (the number too big, eg on the full f2.8 opening) or if i forgot to adjust the iso back if i have shot ambiant light and it is way too high (such as 1600), the TTL cant cope and the picture is still underexposed.
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#8 bcliffe

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Posted 01 April 2011 - 08:09 AM

I believe the answer is no. Since you are shooting TTL, dropping the ISO down will make the camera ask for the flash to put out more power to achieve the same results as when you shot at ISO 100. What you need to do is either shoot manual or if you want to use TTL then use exposure/flash compensation to quite down the amount of light being output.


Cheers
BC

#9 derway

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Posted 01 April 2011 - 10:48 AM

What BC said.

Use the flash exposure compensation. This is the only way to control TTL brightness.
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#10 Jasoncassanova

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Posted 01 April 2011 - 11:22 AM

I see You'r point. Then again many start with manual and use TTL only occasionally. Specially in macro You can achive interesting lighting (shadows etc) with two strobes on different power settings. A long talk in short - start trying manual :) The sooner the better. IMHO TTL gives often boring even lighting ;)

Cheers
Karel



Karel,

Well i might just try that this weekend, it'll be my first to dive with a group of underwater photographers, so this time it'll be long and shallow for us, so i think that gives me a lot of time to experiment :)


Jason.

#11 Jasoncassanova

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Posted 01 April 2011 - 11:33 AM

I am sure you are aware that strobe light can be controlled with strobe power (either manually or by TTL), , distance to subject and aperture. The answers up till now seem to forget the aperture.

For Macro, to get good depth of field (if there is enough light) you can use small apertures (high number such as f16). What are you using normally : i have other ikelite strobes, but if the aperture is too large (the number too big, eg on the full f2.8 opening) or if i forgot to adjust the iso back if i have shot ambiant light and it is way too high (such as 1600), the TTL cant cope and the picture is still underexposed.


i'll keep this in mind, you are right about having a big opening when shooting something up close. Thanks.


Jason.

I believe the answer is no. Since you are shooting TTL, dropping the ISO down will make the camera ask for the flash to put out more power to achieve the same results as when you shot at ISO 100. What you need to do is either shoot manual or if you want to use TTL then use exposure/flash compensation to quite down the amount of light being output.


Cheers
BC



Got it! ;)


Jason.