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buddy

Member Since 20 Jan 2004
Offline Last Active Aug 17 2014 05:04 AM
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Posts I've Made

In Topic: How's my logic...

13 August 2014 - 11:49 PM

yes, that was my thinking. don't know the Tokina personally; using Sigma 15mm f/2.8 on FX with 9" dome or 4"mini dome. Thanks for corrections. 


In Topic: How's my logic...

13 August 2014 - 04:39 AM

I made the switch from D7000 to D800 Nauticam. I convinced myself that the high ISO ability would be useful, cropping etc. But really the big drawbacks are the loss of the Tokina 10-17 (and the ability to use small domes) and the increase in size and weight. I do like the ability to crop drastically but the weight and size is an issue for me. The 16-35 is ok, but seldom wide enough, and I'm not fond of the fisheye look for many subjects with the Sigma 15. I think would stay with the D7000...

 

the 16-35 at 16mm on a FX body (D800) is about the same wide as the 10-17 at 10mm on the D7000 (DX). But the wight and size is certainly an issue...

 

But the IQ of some newer cameras like D810, D4s can let you change the shooting style:

Think about the following scenario:

 

You shoot a dynamic scene (let's say fast moving sharks) in relative deep water with dim ambient lighting conditions. You shoot at f8 and 1/125 sec, 2 flash guns at half power each. The image on the LCD looks ok on the exposure of the shark (foreground) but is too dark on the background, almost black and thus rather underexposed (let's say by -1 stop). But we want blueish water !

 

Now, instead of lengthening the shutter speed to 1/60sec you can do as alternative: change ISO from 100 to 400 (2 stops) plus lowering the flash output to 1/8 power and thus reducing backscatter and decreasing flash recycle time, leaving the aperture unchanged (relative closed at f8) thus conserving DOF (nobody shoots today with f2.8 - 4.0 anymore!), shorten the shutter speed to 1/250sec and thus freezing the action of the moving subjects even more...

 

Off course, that works only with a camera which can handle ISO 400 (or higher, depending on situation) on a neglectable noise level and a high resolution.

 

Wonderful world, isn't it ?

 

Going to Cocos for next 2 weeks and wil try these modern concepts more extensively...


In Topic: exposure impact on ISO variation

11 July 2014 - 08:08 PM

I understand it now in the following way:

 

either change the aperture (by 1 stop in the example) and leaving shutter speed and flash output unchanged

 

or

 

leave aperture unchanged but change flash power output and shutter speed both by 1 stop

 

Why do I ask this?

 

I have had an interesting discussion recently with Kurt Amsler (a well known underwater photographer) and he told me about today's new concepts regarding the virtual no noise sensor cameras at higher ISOs like ISO 400 (I have a D4s now).

 

Think about the following scenario:

 

You shoot a dynamic scene (let's say fast moving sharks) in relative deep water with dim ambient lighting conditions. You shoot at f8 and 1/125 sec, 2 flash guns at half power each. The image on the LCD looks ok on the exposure of the shark (foreground) but is too dark on the background, almost black and thus rather underexposed (let's say by -1 stop). But we want blueish water !

 

Now, instead of lengthening the shutter speed to 1/60sec you can do as alternative: change ISO from 100 to 400 (2 stops) plus lowering the flash output to 1/8 power and thus reducing backscatter and decreasing flash recycle time, leaving the aperture unchanged (relative closed at f8) thus conserving DOF (nobody shoots today with f2.8 - 4.0 anymore!), shorten the shutter speed to 1/250sec and thus freezing the action of the moving subjects even more...

 

Off course, that works only with a camera which can handle ISO 400 on a neglectable noise level.

 

Wonderful world, isn't it ?

 

Anybody else to chime in?

 

 

 

 

 

 

 

 

 

 

 


In Topic: exposure impact on ISO variation

11 July 2014 - 06:25 PM

and what about the shutter speed for the ambient? did you forget about that?

 

Also by 1 stop if changing the ISO 1 stop? or half a stop in aperture plus half a stop in shutter when ISO is changing by 1 stop?

BTW, some flash lights do pretty well with 1/8, 1/4, 1/2 and full power e.g. Subtronics.

thanks


In Topic: FS: Atomos Ninja2 and Underwater Housing DNC-N

10 July 2014 - 07:00 AM

anybody?

 

drop sales price to $1'200!