Digital Cemera Medium Reciprocity Failure

I was doing some night work last night at about 1130 pm and after I'd
finished I was wondering if there's a need to factor in reciprocity failure
for the exposure times when using a digital slr.

Any info would be interesting

--

Martyn

Martyn wrote:
I was doing some night work last night at about 1130 pm and after I'd
finished I was wondering if there's a need to factor in reciprocity failure
for the exposure times when using a digital slr.

No.

Night and Low Light Photography with Digital Cameras
http://www.clarkvision.com/photoinfo...ht.photography

Roger

Martyn wrote:
I was doing some night work last night at about 1130 pm and after I'd
finished I was wondering if there's a need to factor in reciprocity failure
for the exposure times when using a digital slr.

Any info would be interesting

My understanding is no, silicon doesn't have that effect, just thermal
noise.

Cheers,

Wayne

--
Wayne J. Cosshall
Publisher, The Digital ImageMaker, http://www.dimagemaker.com/
Blog http://www.digitalimagemakerworld.com/

"Roger N. Clark (change username to rnclark)"
observed
Martyn wrote:
I was doing some night work last night at about 1130 pm and after I'd
finished I was wondering if there's a need to factor in reciprocity
failure for the exposure times when using a digital slr.

No.

Night and Low Light Photography with Digital Cameras
http://www.clarkvision.com/photoinfo...ht.photography

Fascinating! Thanks, Roger.

Mike
[The reply-to address is valid for 30 days from this posting]
--
Michael J Davis

Some newsgroup contributors appear to have confused
the meaning of "discussion" with "digression".

"Martyn" wrote in message
...
I was doing some night work last night at about 1130 pm and after
I'd
finished I was wondering if there's a need to factor in reciprocity
failure
for the exposure times when using a digital slr.

Any info would be interesting

--

Martyn




No. Reciprocity failure is an effect due to the fact that the
different colours in a film emulsion are designed to work in the
'normal' speed range, say 1/30th - 1/500th give or take (and will work
comfortably over a wider range than that) but when you start to get to
very long exposures the rate at which they work starts to differ and
you get colour casts.

CCDs don't suffer that problem - just noise, which is mainly thermally
generated.


--
Woody

harrogate3 at ntlworld dot com

harrogate3 wrote:

No. Reciprocity failure is an effect due to the fact that the
different colours in a film emulsion are designed to work in the
'normal' speed range, say 1/30th - 1/500th give or take (and will work
comfortably over a wider range than that) but when you start to get to
very long exposures the rate at which they work starts to differ and
you get colour casts.


While you're right that colour casts are introduced for long exposures
(depending on the film), reciprocity failure refers to the fact that a
film essentially becomes less sensitive to light as the exposure time
is increased.

CCDs don't suffer that problem - just noise, which is mainly thermally
generated.


You're right. There is no reciprocity failure with digital.

wrote:
harrogate3 wrote:
No. Reciprocity failure is an effect due to the fact that the
different colours in a film emulsion are designed to work in the
'normal' speed range, say 1/30th - 1/500th give or take (and will work
comfortably over a wider range than that) but when you start to get to
very long exposures the rate at which they work starts to differ and
you get colour casts.


While you're right that colour casts are introduced for long exposures
(depending on the film), reciprocity failure refers to the fact that a
film essentially becomes less sensitive to light as the exposure time
is increased.

CCDs don't suffer that problem - just noise, which is mainly thermally
generated.


You're right. There is no reciprocity failure with digital.


There may not be reciprocity failure, but there is the question of
whether the noise that increases with longer shutter speeds is as bad,
better or worse than the noise that results from higher ISOs.

In other words, from a noise point of view, is it better to stick to
lower ISOs with longer exposure times, or increase the ISO and reduce
the exposure time?

I have done some tests with my Canon EOS 5D but they were not
conclusive. The results may well be different for DSLRs with greater
noise at higher ISOs.

Tony Polson wrote:

There may not be reciprocity failure, but there is the question of
whether the noise that increases with longer shutter speeds is as bad,
better or worse than the noise that results from higher ISOs.


Yes, I think it depends on the sensor, and some experimentation with
one's camera is needed.

In other words, from a noise point of view, is it better to stick to
lower ISOs with longer exposure times, or increase the ISO and reduce
the exposure time?

I have done some tests with my Canon EOS 5D but they were not
conclusive. The results may well be different for DSLRs with greater
noise at higher ISOs.

Well, I have found that my D200, for example, is always better at ISO
100 and arbitrarily long exposures than at higher ISOs and shorter
exposures (this is with DFS on, if off, things may change at very long
exposures).

wrote:


Tony Polson wrote:

There may not be reciprocity failure, but there is the question of
whether the noise that increases with longer shutter speeds is as bad,
better or worse than the noise that results from higher ISOs.


Yes, I think it depends on the sensor, and some experimentation with
one's camera is needed.

In other words, from a noise point of view, is it better to stick to
lower ISOs with longer exposure times, or increase the ISO and reduce
the exposure time?

I have done some tests with my Canon EOS 5D but they were not
conclusive. The results may well be different for DSLRs with greater
noise at higher ISOs.

Well, I have found that my D200, for example, is always better at ISO
100 and arbitrarily long exposures than at higher ISOs and shorter
exposures (this is with DFS on, if off, things may change at very long
exposures).


What is DFS?

Tony Polson wrote:
wrote:

Tony Polson wrote:
There may not be reciprocity failure, but there is the question of
whether the noise that increases with longer shutter speeds is as bad,
better or worse than the noise that results from higher ISOs.

Yes, I think it depends on the sensor, and some experimentation with
one's camera is needed.

In other words, from a noise point of view, is it better to stick to
lower ISOs with longer exposure times, or increase the ISO and reduce
the exposure time?

I have done some tests with my Canon EOS 5D but they were not
conclusive. The results may well be different for DSLRs with greater
noise at higher ISOs.
Well, I have found that my D200, for example, is always better at ISO
100 and arbitrarily long exposures than at higher ISOs and shorter
exposures (this is with DFS on, if off, things may change at very long
exposures).


What is DFS?


Dark Frame Subtraction.