Exposure question ....

northernstar074

northernstar074

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Name
Anthony
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Hi all

I was recently involved in a studio shoot - my first !

I was using f8 and 1/125. Now this got me thinking and I want to check if I am right. If I want to lose some of the DoF would I be right in thinking I could move the f-stop upto f4 or 5.6.

I assume then I would be able to use f5.6 and 1/250 or f4 and 1/500 !?!?!?!

Am I wrong somewhere or does it not work the way I think it does ?

Very confused !!! lol :thinking:
 
All depends on the lights used ( max sync speed ) Studio lights will have a max sync speed but if you were using a flash gun you may be able to get faster sync speeds.

What was the set up & camera mode used ?
 
If you are working in a studio environment where you have a certain level of lighting then I'm afraid it's not as simple as just lowering the f number you use to reduce the depth of field you are getting because the amount of light entering the camera will increase and you'll massively over expose your shot.

Increasing the shutter speed won't help in a studio because the duration of the flash is only about 1/1000th of a second so whether you have a shutter speed of 1/60th or 1/250th you'll get pretty much the same exposure.

The only way to reduce the DoF in a studio envorinment would be to reduce the power of the lighting to such a level that you expose correctly at around f4 and 1/125th. Personally I've never tried it in a studio though.
 
You could keep the speed and decrease the power of the lights. Some cameras have a max synch speed of 1/250 or less. Experimentation is the best teacher on this one.
 
Not sure on the lighting set up but can find out.

Wasn't using a flash gun.

I was using manual and set the aperture and shutter speed myself and left the white balance and ISO and auto but shot in raw.

I did notice in lightroom, as I had a play with the camera during the shoot, that some of the photos are at f4.8 and 1/1000. One of the best was taken at f4.8 1/1000 42mm ISO 400. That confused me !!!!
 
-Rob- said:
If you are working in a studio environment where you have a certain level of lighting then I'm afraid it's not as simple as just lowering the f number you use to reduce the depth of field you are getting because the amount of light entering the camera will increase and you'll massively over expose your shot.

Increasing the shutter speed won't help in a studio because the duration of the flash is only about 1/1000th of a second so whether you have a shutter speed of 1/60th or 1/250th you'll get pretty much the same exposure.

The only way to reduce the DoF in a studio envorinment would be to reduce the power of the lighting to such a level that you expose correctly at around f4 and 1/125th. Personally I've never tried it in a studio though.
Click to expand...

Cheers Rob ! This now makes some sense out of me getting a decent photo at f4.8 with 1/1000 !
 
ianbarber said:
Dont forget that the Shutter speed will only affect the ambient and not the flash exposure.
Click to expand...

Thanks Ian and thanks to you all for your help !

Just a side note - are my calculations on my first post correct with regards to the shutter speed and aperture adjustments ?

f8 at 1/125, f5.6 at 1/250 and f4 at 1/500 would give the same exposure ?
 
northernstar074 said:
Not sure on the lighting set up but can find out.

Wasn't using a flash gun.

I was using manual and set the aperture and shutter speed myself and left the white balance and ISO and auto but shot in raw.

I did notice in lightroom, as I had a play with the camera during the shoot, that some of the photos are at f4.8 and 1/1000. One of the best was taken at f4.8 1/1000 42mm ISO 400. That confused me !!!!
Click to expand...

I would say that if you best shot was at the above settings it couldn't have had any flash in the shot ( from studio lights ) just ambient light.
 
northernstar074 said:
Cheers Rob ! This now makes some sense out of me getting a decent photo at f4.8 with 1/1000 !
Click to expand...
If my explaination made that make sense then I've obviously explained it wrong because at a shutter speed of 1/1000 you are shooting above your cameras maximum flash sync speed so as has been mentioned, you won’t be capturing any of the flash light, just ambient light. I guess if you had your camera set on auto ISO then you’ll probably find your camera has shot at about 1,000 ISO so compensate for the fast shutter speed.

northernstar074 said:
Thanks Ian and thanks to you all for your help !
Click to expand...
northernstar074 said:

Just a side note - are my calculations on my first post correct with regards to the shutter speed and aperture adjustments ?

f8 at 1/125, f5.6 at 1/250 and f4 at 1/500 would give the same exposure ?
Click to expand...

If you were shooting outdoors without flash then yes, you’re not far wrong but when using flash where the light only last for about 1000th of a second your calculations won’t apply.
 
northernstar074 said:
Thanks Ian and thanks to you all for your help !

Just a side note - are my calculations on my first post correct with regards to the shutter speed and aperture adjustments ?

f8 at 1/125, f5.6 at 1/250 and f4 at 1/500 would give the same exposure ?
Click to expand...

Yes. That's correct. It would work fine in normal continuous (ambient) light. But not flash.

Most people seem to be assuming that when you said studio that meant flash, but if you were not using flash, then that's okay.

The problem with flash is how the focal plane shutter in all DSLRs works (google) which basically means that when the shutter speed rises above the max x-sync speed (usually around 1/200sec) you only get part of the picture exposed.

Even if you did use flash, you could still do it if you could reduce the power of the flash, or if you had enough movement on the ISO. For example, you are wanting to reduce the f/number by two stops so if you are at ISO800 you could drop that to ISO200 and retain correct exposure.
 
Definitely get the ISO off auto, I would be using ISO 80-100 in a studio, this will have the effect of forcing you to use larger apertures.
 
-Rob- said:
Are you able to post this photo that was shot at 1/1000th sec with the exif details so we can try and understand how it came out looking so good?
Click to expand...

4795167661_5bf2e8ac0f.jpg
 
Seems to have lost the exif data ! :(

Here it is in full:

Exif data
Camera NIKON CORPORATION NIKON D40
Exposure 0.001 sec (1/1000)
Aperture f/4.8
Focal Length 35 mm
ISO Speed 400
Exposure Bias -1/3 EV
Flash No Flash
File Size 2.2 MB
File Type JPEG
MIME Type image/jpeg
Image Width 2865
Image Height 1994
Encoding Process Baseline DCT, Huffman coding
Bits Per Sample 8
Color Components 3
X-Resolution 240 dpi
Y-Resolution 240 dpi
Software Ver.1.11
Date and Time (Modified) 2010:07:08 18:44:51
Exposure Program Shutter speed priority AE
Date and Time (Original) 2010:07:07 19:30:54.60+01:00
Date and Time (Digitized) 2010:07:07 19:30:54
Max Aperture Value 4.6
Subject Distance 2.11 m
Metering Mode Multi-segment
Light Source Unknown
User Comment (C) ANTHONY BRADSHAW 2010
Sub Sec Time Original 60
Sub Sec Time Digitized 60
Sensing Method One-chip color area
CFAPattern [Blue,Green][Green,Red]
Custom Rendered Normal
Exposure Mode Auto
White Balance Auto
Digital Zoom Ratio 1
Focal Length In35mm Format 52 mm
Scene Capture Type Standard
Gain Control Low gain up
Contrast Low
Saturation Normal
Sharpness Normal
Subject Distance Range Unknown
Compression JPEG (old-style)
Viewing Conditions Illuminant Type D50
Measurement Observer CIE 1931
Measurement Flare 0.999%
Measurement Illuminant D65
XMPToolkit Adobe XMP Core 4.2-c020 1.124078, Tue Sep 11 2007 23:21:40
Creator Tool Adobe Photoshop Lightroom
Lens 18.0-55.0 mm f/3.5-5.6
Lens ID 148
Image Number 7456
Color Transform YCbCr
Flash Return No return detection
Flash Mode Unknown
Flash Function False
Flash Red Eye Mode False
 
northernstar074 said:
Seems to have lost the exif data ! :(

Here it is in full:

Exif data
Camera NIKON CORPORATION NIKON D40
Exposure 0.001 sec (1/1000)
Aperture f/4.8
Focal Length 35 mm
ISO Speed 400
Exposure Bias -1/3 EV
Flash No Flash
File Size 2.2 MB
File Type JPEG
MIME Type image/jpeg
Image Width 2865
Image Height 1994
Encoding Process Baseline DCT, Huffman coding
Bits Per Sample 8
Color Components 3
X-Resolution 240 dpi
Y-Resolution 240 dpi
Software Ver.1.11
Date and Time (Modified) 2010:07:08 18:44:51
Exposure Program Shutter speed priority AE
Date and Time (Original) 2010:07:07 19:30:54.60+01:00
Date and Time (Digitized) 2010:07:07 19:30:54
Max Aperture Value 4.6
Subject Distance 2.11 m
Metering Mode Multi-segment
Light Source Unknown
User Comment (C) ANTHONY BRADSHAW 2010
Sub Sec Time Original 60
Sub Sec Time Digitized 60
Sensing Method One-chip color area
CFAPattern [Blue,Green][Green,Red]
Custom Rendered Normal
Exposure Mode Auto
White Balance Auto
Digital Zoom Ratio 1
Focal Length In35mm Format 52 mm
Scene Capture Type Standard
Gain Control Low gain up
Contrast Low
Saturation Normal
Sharpness Normal
Subject Distance Range Unknown
Compression JPEG (old-style)
Viewing Conditions Illuminant Type D50
Measurement Observer CIE 1931
Measurement Flare 0.999%
Measurement Illuminant D65
XMPToolkit Adobe XMP Core 4.2-c020 1.124078, Tue Sep 11 2007 23:21:40
Creator Tool Adobe Photoshop Lightroom
Lens 18.0-55.0 mm f/3.5-5.6
Lens ID 148
Image Number 7456
Color Transform YCbCr
Flash Return No return detection
Flash Mode Unknown
Flash Function False
Flash Red Eye Mode False
Click to expand...

Hi Anthony, i think because of the reasons i've highlighted in your exif data you got this shot because of the modelling light on the flash head but had nothing to do with the actual flash. You need to be in manual mode on the camera for studio flash & the speed is simply too fast.

What is your location? i.e are you up north as your name suggests?
 
Hi Chris
Yes I am up north - Southport, Merseyside to be precise :)
Thanks for your reply. This was one of the first photos I took before the camera was switched to manual f8, 1/125, ISO 200.
 
Thanks anyway Chris !

Next time I am passing the New Forest :)

It was my first studio shoot but will be doing more to get more experience and understanding.
 
northernstar074 said:
Hi Chris
Yes I am up north - Southport, Merseyside to be precise :)
Thanks for your reply. This was one of the first photos I took before the camera was switched to manual f8, 1/125, ISO 200.
Click to expand...
Next time you are off to the studio then put your camera on these settings before you leave the house and you won't go far wrong when you start shooting. Brian said he always has his lights set up for ISO200 at f8 so it's the only setting you'll need if you go back to shoot there.
 
-Rob- said:
Next time you are off to the studio then put your camera on these settings before you leave the house and you won't go far wrong when you start shooting. Brian said he always has his lights set up for ISO200 at f8 so it's the only setting you'll need if you go back to shoot there.
Click to expand...

Cheers Rob. I was experimenting when I went wandering off onto f4 1/1000 ;)
 
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