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How different are the P45+ and P30+ as regards long exposures and noise levels?

dougpeterson

Workshop Member
1) Absolutely essential (for best results) to ensure your back has the latest firmware. Check under Menu > Configuration > About. If you don't have 5.1.2, and especially if you have something very old like 2.9.8 you will see much better results with longer exposures. More Info.

2) If you shoot four four-minute exposure in a row (just to select a specific example) without allowing the back to cool down then the noise in the image will be similar to a sixteen minute exposure. It's perfectly reasonable to adopt a workflow whereby you shoot as many frames quickly as you need to asses framing/exposure etc (including using high ISO images to estimate final proper exposure) and then wait a few minutes before capturing the "keeper".

3) Judging the back's temperature is not something that's really that easy to do. The entire chasis is constructed as a big heat sink, so it's not only normal to see the outside frame become warm/hot - it's the entire point! The only temperature that matters for long exposure noise purposes is the internal temperature of the back. The heat is pulled away from the sensor/A-D convertor to the exterior of the back where a large surface area can dissipate that heat into the air quickly (and without a fan).

4) Capture One versions and raw processing settings also matter a lot. Keep in mind that if you "push" the file one stop in post (a.k.a. +1 Exposure in C1) means you are effectively doubling the length of the exposure in post. So if you're temperature-limit was 10-minutes and you expose in-camera for 5 minutes and then slide exposure up to +1 in Capture One you will be going past the "maximum" - the world will not end but your noise levels will likely be higher than you want. The same principal applies to any image adjustment which increases exposure in the shadows (e.g. shadow recovery, curves, lens-vignette or LCC adjustments). NEVER try Lightroom/Aperture/etc/etc to process long exposures from Phase One - stick with Capture One, and specifically stick with Capture One 5.1.2 (or whatever the latest is when you read this).

With all that in mind: a P30+ back with recent firmware and which is shot when it's had a chance to cool off will behave very much in accordance to Phase One Long Exposure Guide which we have on our website. That of course is showing the maximum, so it's always a good idea to be conservative where possible.

P.S. Our company name is "Capture Integration", not "Capture One" (no worries of course - I just thought I'd clarify to avoid confusion of any other readers).

Doug Peterson (e-mail Me)
__________________
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Jack

Sr. Administrator
Staff member
Thanks for the clarifications Doug! And FWIW, as respects the names, I often use "CI" when referring to Capture Integration, and "C1" when referring to PhaseOne's Capture One processing software -- it's unfortunate the letter *I* and the number *1* look so similar online. My bad.
 

Audii-Dudii

Active member
2) If you shoot four four-minute exposure in a row (just to select a specific example) without allowing the back to cool down then the noise in the image will be similar to a sixteen minute exposure. It's perfectly reasonable to adopt a workflow whereby you shoot as many frames quickly as you need to asses framing/exposure etc (including using high ISO images to estimate final proper exposure) and then wait a few minutes before capturing the "keeper".
Last night, I did some more testing instead of photographing (grrr...) and confirmed that shooting several long exposures virtually consecutively does indeed appear to have been the source of my noise problem. What's not yet clear, though, is how long I should allow the back to cool between exposures to prevent noise from being a problem in the future. Or if this can be sped up any by providing some external cooling via a fan, as I am often setup in the middle of a street and the local police prefer that I disrupt traffic for as short a period of time as possible.

4) Capture One versions and raw processing settings also matter a lot. Keep in mind that if you "push" the file one stop in post (a.k.a. +1 Exposure in C1) means you are effectively doubling the length of the exposure in post. So if you're temperature-limit was 10-minutes and you expose in-camera for 5 minutes and then slide exposure up to +1 in Capture One you will be going past the "maximum" - the world will not end but your noise levels will likely be higher than you want. The same principal applies to any image adjustment which increases exposure in the shadows (e.g. shadow recovery, curves, lens-vignette or LCC adjustments). NEVER try Lightroom/Aperture/etc/etc to process long exposures from Phase One - stick with Capture One, and specifically stick with Capture One 5.1.2 (or whatever the latest is when you read this).
I understand the relationship between tweaking the image and increasing the presence of noise, but I wasn't aware that the relationship between doing so pre- and post-exposure is 1:1, which is how I read your comments. In any event, I am using the latest version of Capture One and it does appear that I was not using its NR tools aggressively enough. Needless to say, I'm looking forward to the Capture Integration (see? I got it right this time!) Capture One seminar in October as I have a lot of learning to do before I'm able to master it!

Oh, and for the record, my P30+ also has the latest firmware version installed, as that's how I received it fresh from Denmark after it was replaced during my recent Hasselblad H-to-Contax mount conversion.

With all that in mind: a P30+ back with recent firmware and which is shot when it's had a chance to cool off will behave very much in accordance to Phase One Long Exposure Guide which we have on our website. That of course is showing the maximum, so it's always a good idea to be conservative where possible.
In view of my experience, perhaps you might consider adding a third note to the chart to the effect that multiple consecutive long exposures can equal the effect of a single long exposure of the same length? In retrospect, this seems fairly obvious, I know, but I'm generally not a dumb guy and I didn't consider this until it smacked me upside the head this past Friday night.

Getting back to my original question, though: If the P45+ is the best Phase One has to offer as regards long exposures, are you able to quantify how much better it is than the P30+? While I would prefer to let my budget recover a bit before I think about upgrading, if the difference between them is significant enough -- say, 20%, whatever that might mean -- I might consider it anyway as many of the images I capture are quite ephemeral and I may not have a chance later to capture them again.

P.S. Our company name is "Capture Integration", not "Capture One" (no worries of course - I just thought I'd clarify to avoid confusion of any other readers).
Yet another instance of brain fade on my part. My apologies...
 
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dougpeterson

Workshop Member
Getting back to my original question, though: If the P45+ is the best Phase One has to offer as regards long exposures, are you able to quantify how much better it is than the P30+? While I would prefer to let my budget recover a bit before I think about upgrading, if the difference between them is significant enough -- say, 20%, whatever that might mean -- I might consider it anyway as many of the images I capture are quite ephemeral and I may not have a chance later to capture them again.
In my experience the P45+ is a bit better than the 30+ in regards to long exposure. I can't offer a technical explanation as I believe the difference is more than the obvious: smaller noise size for any given print size because of the higher resolution. However my experience is enough to indicate it'd be worth it for you to do your own further testing.

Doug Peterson (e-mail Me)
__________________
Head of Technical Services, Capture Integration
Phase One, Leaf, Cambo, Canon, Apple, Profoto, Eizo & More
National: 877.217.9870 *| *Cell: 740.707.2183
Newsletter: Read Latest or Sign Up
RSS Feed: Subscribe
Buy Capture One at 10% off
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dougpeterson

Workshop Member
Quick reminder note: the P30+ has microlenses while the P45+ does not. The base ISO of the P30+ is therefore ISO100 while the P45+ has a base ISO of 50. When I said the 45+ was slightly better than the 30+ at long exposures I meant in terms of being able to achieve the longest exposure in minutes for any given temperature. This equation may change if instead you are trying to gather the right amount of light for an exposure in a given fixed-lighting scene where the one stop gain in ISO may negate the higher ceiling in minutes.
 

Jack

Sr. Administrator
Staff member
FWIW,

Here is a 30 minute capture at ISO *100* off the P45+. I used ISO 100 because I only had about 1/4 battery left and wasn't sure it would hold for a full hour. In the end, I still had a 1/4 battery after the 30 minutes of exposure and 30 of darkframe, so for whatever reason the backs don't seem to use a lot of power during the long exposure process:

 

Audii-Dudii

Active member
This equation may change if instead you are trying to gather the right amount of light for an exposure in a given fixed-lighting scene where the one stop gain in ISO may negate the higher ceiling in minutes.
Well, since lighting rarely gets more fixed than it does with streetlights, which is how the scenes I photograph are illuminated, it sounds like the only benefit I'll see from a P45+ versus my P30+ are larger files and higher resolution. :cool:

FYI, in case anybody is curious, here's the very first image I captured with the Contax/P30+ combo ... clearly, I still have a learning curve to climb here but aside from the noise issues, the results thus far do seem promising.

 
S

SCHWARZZEIT

Guest
FWIW,

Here is a 30 minute capture at ISO *100* off the P45+. I used ISO 100 because I only had about 1/4 battery left and wasn't sure it would hold for a full hour. In the end, I still had a 1/4 battery after the 30 minutes of exposure and 30 of darkframe, so for whatever reason the backs don't seem to use a lot of power during the long exposure process:

Really beautiful image, Jack.
However, even at this size the top area looks slightly noisy. Maybe it's just the web compression. Could you show a 100% crop from the top right area?

-Dominique
 

Jack

Sr. Administrator
Staff member
Dominique, I could dig the original up, but I can tell you it is a "noisy" image by any conventional measure. In fact, it is a good argument to stick to base ISO with these backs when doing long exposures. On the upside, the noise is only obvious in the even-toned areas -- which in this image is the entire sky.

As a side-bar, what I found more interesting with long exposures on the P45+ was the fact that stars rendered their actual color more intensely than I'd ever seen with similar film captures.
 

cly

Member
I can tell you it is a "noisy" image by any conventional measure. In fact, it is a good argument to stick to base ISO with these backs when doing long exposures.
jack - could you say something about noise in the range of 1-5 minutes? what about dynamic range?

--chris
 

Jack

Sr. Administrator
Staff member
jack - could you say something about noise in the range of 1-5 minutes? what about dynamic range?

--chris
I never really did very many shots in that range. Most of my "long exposure" frames were 15 or 30 seconds. I can tell you there that at ISO 50 they were exceptionally clean, though still visibly noisier than sub 1 second shots.

Here's a 30 second, ISO 50, P45+ capture:



Here is a 100% crop from the above frame, C1 NR set to 0/40/0 (Lum/color/long exp):

 

cly

Member
once more: thanks a lot, jack!

What a forum! Where else can you order up crops from an image and have them delivered within an hour? :)
and not only that, it's one of the, pretty rare, friendly places in the web :)

compliments to jack and guy and everyone participating for keeping this a place where most discussions don't end in useless verbal fights!

--chris
 

mtomalty

New member
Doug,
Out of curiosity,if one does a twenty minute exposure, for example, does
the black frame exposure process also contribute heat or can it be considered
part of the cool down cycle

Mark
 

Dave Gallagher

Active member
Doug,
Out of curiosity,if one does a twenty minute exposure, for example, does
the black frame exposure process also contribute heat or can it be considered
part of the cool down cycle

Mark
Mark

The chip is powered and is exposing even though there is no light hitting the sensor. So yes, it does create heat and noise and is not a part of the cool down process.

Sincerely,

Dave Gallagher
President
Capture Integration
www.CaptureIntegration.com

Phase One, Leaf, Leica, Cambo, Canon, Nikon, Apple, Profoto, Broncolor, Arca Swiss, Eizo, LaCie & More

404-522-7662 | Atlanta
305-350-9900 | Miami
877-217-9870 | National
770-846-5223 | Cell
 
S

sonar

Guest
Hi, I just wondered if someone could please let me know what "black frame exposure process" means. I would like to transition from MF film to digital and am considering purchasing a p30+ or p45+ back for long exposure work. I have never heard this term before though.

Oh, and great information here, thank you!
 

GrahamWelland

Subscriber & Workshop Member
black frame exposure process:

Here's a brief summary, although there's more to it than just this:

After the shot has been taken a second exposure is made by the back - the dark frame - which has no light hitting the sensor but the noise signature of the back is recorded. This 'exposure' takes the same amount of time as the original shot since you need to let the heat/signal noise build up. This dark frame is then processed against the original image to remove/reduce this background noise from the shot.
 
S

sonar

Guest
Very interesting. Is this something you do manually? Is there an automatic feature for this with Phase One backs? Is it something you would do only for long exposures, or in general?

Thanks.
 
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