Like I say ... Two stupid question about White Balance and IsoSettings

1. Iso Settings

In my last trip I was forced to use ISO 400 becuace off the visability and contast etc...

With ISO 200 I have times that was lower that 1/80 and I was scared that my Photos may be blury.

I have use F5,6 most off the time and was shooting with a 10,5mm lens

I was thinking that :
a:) The camera focus better with ISO400
b:) The shutterspeed must be always higher that 1/100 for freediver photos..

But maybe I miss a point and there is a other solution to take the shoots and still use ISO 200

The Nikon D70s have a lot off grain in ISO 400. Then the Photos lose in detail in higher isos color Noice is a problem to..

So guys, untill I break in in Alex's appartmet and take the famus D2X
what can I do ?

Then

2. White Balance....

There is a funktion in my Nikon D70s that you can set the white balance from a reference Photo...

So, If I have a photo with perfect white balance and I shoot in the same deapth and same contitions (light etc...) can I use this photo as reference?

Lambis

Hi Lambis

Just to pass on my knowledge on this subject.

firstly

WB, You need not worry really if your Shooting RAW, you can sort it later in PS

but your assumption is more than likely correct, however, as long as the lighting conditions stay the same.

as for you information on ISO

I've done a lot of shooting for various magazine articles. all shots are normally done ON THE FLY.. shots of divers training etc etc..

A simple rule that shutter speed should be equal to Focal length or greater to capture a sharp image. WITHOUT FLASH. whilst hand holding

I suppose it depends on if your using flash or not in your case

I have on many many occasions shot 24mm with F5.6 100ISO 1/30 1/15 and still ended up with crisp good images.

good bouyancy control is also a strong player.

if your base is 1/100 then i guess your shooting without flash your subjects are moving quite fast and your trying to freeze them ?

flash should freeze your frame at 1/30 1/60 no worries

another thing to think about whilst snapping this type of subject is flash sync and TTL or not to TTL.

First curtain flash with a slow shutter speed and faster moving subject would not give the correct effect, i'd choose rear curtain and have any motion blur behind my subject.

I'd guess for instance.... your free diver returning to the surface "quite fast i'd guess if he's high on CO2" not wanting to wait around for a pose !!

ITTL would also be an issue here as well, the small pre-flashes that ITTL fires would not produce the best image during rear curtain usage.

I've found that ITTL gives a very slight multiple ghosting effect as the preflashes are fired at the start of the shutter opening for ITTL metering then the final flash prior to the shutter closing all this is being recorded during rear curtain sync.

GOOD OLD manual flash works best here as there is 1 flash of light and thats the light that freezes your subject and nothing more just prior to the shutter closing.


I remember reading somthing from Alex M regarding this when he tested a rig of SB80's .... and D-TTL "i think"


go try it with a sb800 and a moving car at night time you see what i mean

well thats just my input on the subject, not of any use i suppose.

but it might have touched something

regards

craig

Craig. I dont use Flash.. just magic filter...

About that shutter speed should be equal to Focal length??

10,5mm focal length??

Lambis

Hi Lambis

Yeh that would be correct in the field of wildlife photography

is i were shooting a 400mm tele lens i'd need a 1/400 at least to be sure of a sharp image free of camera shake hand held.. depends on how good you are hand holding though as well.

Not sure if you can apply this to WA shooting

1/10 seems very slow to me for moving subjects...

i should think 1/30 is possible with practise

your only other option is to open the aperture up if your using ISO 200

regards

craig

Lambis, that's a rule that we use. 10.5 focal length = 1/10 speed. This will be a bit too slow especially for close ups of moving free divers, but I think you can safely use 1/50 and won't notice blur on the 10.5 lens. Anyways, it is digital! Experiment!

Also, I am surprised that you are seeing noise with the D70 at ISO400. Noise should only start to appear at ISO 800 on the D70. Have you tried applying noise reduction in Nikon Capture? It does get rid of the noise while preserving the detail.

Luiz

Thanks craig...

About good bouyancy control... guys I am freediving all the time.
Bouyancy is out off question....maybe when I am down to 15mm I can arhive bouyancy but most off the time I move the way my subject move try to have the same speed and just focus on framing, while moving..

Maybe , next time I must go one week earlier so that I have time to test new ways...

Thanks for the help my friends

I havent try Nikon Capture. but I will do it.
I think that my noice problem is a compination off many aspects.
Sandy water, low viz, low contrast, high isos. A coctail that just not work for me.

Hi Lambis

no worries

I'm off to the Maldives next weekend, and have a magic fliter myself, intend to do lots of snork'in with my D70 and Magic,

so hopefully i will have somthing to post when i get back

regards

craig

I use capture 4.3 as well as PS, it is atually quite good, also try looking at www.fredmiranda.com

fred does a lot of plug'ins for PS that actually work quite well, i use his

DRI pro
ISO NX reducer

with great success

Also, check out your inc camera sharpening whilst using iso 400, have it set to normal and work on it later

Thanks Craig.. Will be intresting to hear about you Amldives trip

I will check fredmiranda . Normaly I use Rawshooter for Raw editing
Lambis

Hmm.. You bring up a very good question, Lambis.

"Does increasing the ISO improve auto-focus?"

I thought it might but my very unscientific tests say that it DOESN'T. This was based simply on focusing at home in an area of low light with the 100mm 2.8 lens while attempting to notice a auto-focus speed difference between ISO 100 and ISO 3200 on the Canon 20D.

I suppose the question as to why it doesn't is best left to the engineering folks on the board. My (uneducated) guess is that increasing the ISO doesn't increase the sensitivity of the CMOS/CCD but amplify (lets say) the voltage registered at every pixel on the sensor. Dunno.. Like I said, I'm sure some of the engineering folks in here might help elucidate on the answer.

Hi Lambis (and Laz),

Autofocus is performed by a set of sensors in the mirror box, not by the CCD/CMOS - so adjusting your ISO has no affect on the AF.

Cheers
James

Lambis I understand that you are seeing noise at 400ISO and suggesting it may be a result of sandy water, low viz, low contrast and ISO setting. The one thing you might try is making sure that you are pushing the exposure histogram as far to the right as you can. This can be difficult when you have very bright highlights in which you want to maintain detail, but if you are exposing mainly for the blue background, my suggestion is to really watch the histogram. If you underexpose on any camera at any ISO, you will tend to get noise. Just a suggestion anyway.

Lambis, I ALWAYS shoot ISO 400 with my D70 when shooting underwater. The reason I do is that I value faster shutter speeds and higher f stops more than I do the slight increase in noise.

http://www.splashdowndivers.com/photo_gall...ettings_iso.htm