Luminous Landscape Forum
Equipment & Techniques => Medium Format / Film / Digital Backs – and Large Sensor Photography => Topic started by: PaulSchneider on April 16, 2010, 01:00:29 pm
-
Hi guys,
I just had a talk with a someone about long exposure times in architectural photography. He said that the p45+ is still a de facto standard among architectural photographers because of its ability to make exposures of up to one hour. He went on to say that for example during the blue hour this can come in handy.
In this regard I have two questions:
1. How can you expose for one hour at night without getting a completely white image anyways?? I mean, even at an aperture of 16 and at ISO 50 ... after 3600 seconds, there must be enough light to completely blow out the sensor? Down my street at night for example, at an aperture of f8 and with iso 50 I get an exposure time of a few seconds ... but a lot less than a minute even! Can somebody explain to me how such long exposures are even possible?
2. If one has a P65 back for example, can one do all tasks in architectural photography with it or are there scenarios where the long exposure capability of the P45+ enables a special kind of photography otherwise not possible?
Thank you for your explanations,
regards
Paul
-
I just had a talk with a someone about long exposure times in architectural photography. He said that the p45+ is still a de facto standard among architectural photographers because of its ability to make exposures of up to one hour. He went on to say that for example during the blue hour this can come in handy.
In this regard I have two questions:
1. How can you expose for one hour at night without getting a completely white image anyways?? I mean, even at an aperture of 16 and at ISO 50 ... after 3600 seconds, there must be enough light to completely blow out the sensor? Down my street at night for example, at an aperture of f8 and with iso 50 I get an exposure time of a few seconds ... but a lot less than a minute even! Can somebody explain to me how such long exposures are even possible?
2. If one has a P65 back for example, can one do all tasks in architectural photography with it or are there scenarios where the long exposure capability of the P45+ enables a special kind of photography otherwise not possible?
An HOUR is indeed a very rare exposure requirement - those looking for star trails when there isn't much moon light and in an area without much light pollution would be an example. Technically speaking the back can go for much longer if it is colder than 64F/18C (chart of temp vs max exposure (http://www.captureintegration.com/phase-one/phase-one-tech-specs/)). However, 4-15 minute exposures are not uncommon at all.
The following factors lead up to longer exposures:
- f/16 is not uncommon, f/22 is less common but used
- everything that can be shot at ISO50 is shot at ISO50
- graduated ND filters, polarizes, light source filters (yes there is still good technical reasons to use these even when shooting raw) are more common in architecture than in most styles of photography
- moderate to extreme camera movement (significant rise) comes with either vignetting or center filters (either way less light)
- bracketing to get detail in areas of deep covered shadow can require several more stops than the general exposure
- when adding your own light into the scene the ability to do a longer exposure means you can carry less powerful lights in your kit, which usually means more lights on a particular circuit or generator and less expensive rental/purchase/replacement. one of our favorite architectural shooters, Jeffrey Jacobs, (bias alert: we do architectural lighting workshops (http://www.captureintegration.com/2010/02/15/atlanta-jeffrey-jacobs/) with him) works mostly with (hundreds of) household tungsten lights when lighting interiors
So yes, most of our architectural customers are opting to stay with the P45+ which is the best camera system on the market for very long exposures. The P65+ is a fantastic back and I know a lot of architectural shooters who would love the additional resolution (heresy amongst those who assume no one needs more than 20ish megapixels, but it's true), but it's not the right back if long exposures are a requirement or mainstay of your work.
Also keep in mind that with a Phase One, or any other back, there is usually a stated maximum exposure which represents the longest exposure which is still "pretty good" but if you're looking for the absolute maximum quality (especially regarding shadow noise and color accuracy) then you'll probably want to stay a good margin away from that absolute longest exposure.
Doug Peterson ()
__________________
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 (http://www.captureintegration.com/our-company/newsletters/)
RSS Feed: Subscribe (http://www.captureintegration.com/2008/08/11/rss-feeds/)
Buy Capture One at 10% off (http://www.captureintegration.com/phase-one/buy-capture-one/)
Personal Work (http://www.doug-peterson.com/)
-
1. How can you expose for one hour at night without getting a completely white image anyways?? I mean, even at an aperture of 16 and at ISO 50 ... after 3600 seconds, there must be enough light to completely blow out the sensor? Down my street at night for example, at an aperture of f8 and with iso 50 I get an exposure time of a few seconds ... but a lot less than a minute even! Can somebody explain to me how such long exposures are even possible?
Paul,
It's pretty simple,really. After all, in a different situation it's equally possible to blow out a frame to white shooting at 1/250 @ f8
If you're shooting a well lit building at dusk at 'normal' apertures without neutral density filters,polarizer,etc then it's reasonable to expect that much shorter exposure times are required.
Shoot down a dark alley with a minimal light source behind you in a situation where you require f16 to maintain depth of field and suddenly seconds become minutes.
Shooting certain landscape imagery under cover of a tree canopy and using a polarizer at f 16 will quickly rocket you to multi minute exposures.
Most backs from every manufacturer apart, really, from the P45+, or to a slightly lesser degree the Hasselblad H4d-40, become so heavily noise-ridden at exposures beyond 30-40 seconds as to be useless for this task.
If you're shooting subjects that don't require exposure times longer than 30-40 seconds then you have a ton of options.
If not, you really have only two options available.
Mark
www.marktomalty.com
-
Most backs from every manufacturer apart, really, from the P45+, or to a slightly lesser degree the Hasselblad H4d-40, become so heavily noise-ridden at exposures beyond 30-40 seconds as to be useless for this task.
Though we hold the P45+ up as being the king in this regard the P20+, P21+, P25+, and P30+ are also rated at 1-hour maximums (for 64F air temperature). I've not seen any super long exposures from these backs (when someone is interested in really long exposures we always encourage them to buy/rent a P45+) but I done 20 minutes with a P30+ and many minute exposures with the other backs - they don't break a sweat.
The P45 non plus can also do several minutes (though not the many minutes or hours that the plus version can handle).
Doug Peterson ()
__________________
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 (http://www.captureintegration.com/our-company/newsletters/)
RSS Feed: Subscribe (http://www.captureintegration.com/2008/08/11/rss-feeds/)
Buy Capture One at 10% off (http://www.captureintegration.com/phase-one/buy-capture-one/)
Personal Work (http://www.doug-peterson.com/)
-
Hi Doug,
a P25+ shooter has told me that with long exposures, the back requires the same length of exposure time to be ready to shoot again. Is there any true to this?
Regards
Michael
-
I've heard this a few times and I just don't get it. I've been shooting architecture with the P65+ for 10 months and I've NEVER needed an exposure longer than 9 seconds. Usually I'm at 1-3 seconds for interiors... including bracketing for shadows.
Most common settings on interiors: 45mm lens f 11 1/2 @ 1s, Iso 50... maybe 100 if my strobe is weak.
*scratches head*
-
a P25+ shooter has told me that with long exposures, the back requires the same length of exposure time to be ready to shoot again. Is there any true to this?
I'll let Doug answer that specifically for the PhaseOne backs, but the procedure is generally called "Dark frame subtraction (http://en.wikipedia.org/wiki/Dark_frame_subtraction)".
From what I've heard, Sinar backs can intermittently take dark frames which can then be averaged for similar exposure times. Averaging multiple dark frames gives better results than a single darkframe. A drawback of using only dark frames is that the random noise level is increased during subtraction, although the systematic/pattern noise is reduced. It's better to also remove bias (read) noise (by using black frames). It would be interesting to learn if the PhaseOne backs employ such strategies.
Cheers,
Bart
-
I have a Phase One back, and for long exposures it does take a "dark frame" to help reduce image noise.
David
-
Doug:
I hope my question is answerable:
How many minutes can a P45 (non+) go without building noise for a 24X30" print? My goal would be 4-8 minute exp with ND's
TIA
CBarret:
I often shoot interiors (dark, like bars) with my 5D2 and my exposures can go to 30 secs.
Eduardo
Though we hold the P45+ up as being the king in this regard the P20+, P21+, P25+, and P30+ are also rated at 1-hour maximums (for 64F air temperature). I've not seen any super long exposures from these backs (when someone is interested in really long exposures we always encourage them to buy/rent a P45+) but I done 20 minutes with a P30+ and many minute exposures with the other backs - they don't break a sweat.
The P45 non plus can also do several minutes (though not the many minutes or hours that the plus version can handle).
Doug Peterson ()
__________________
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 (http://www.captureintegration.com/our-company/newsletters/)
RSS Feed: Subscribe (http://www.captureintegration.com/2008/08/11/rss-feeds/)
Buy Capture One at 10% off (http://www.captureintegration.com/phase-one/buy-capture-one/)
Personal Work (http://www.doug-peterson.com/)
-
Chris,
I wonder the same thing. I'm in the same boat as you. I dont see any use for long exposures in architectural photography unless for some reason you are trying to capture blurred clouds at dusk.
Eduardo,
You must use very little lighting, if any.
-
I hope my question is answerable:
How many minutes can a P45 (non+) go without building noise for a 24X30" print? My goal would be 4-8 minute exp with ND's
We'd be happy to rent you such a system (with credit towards purchase) so you can see yourself. If you're more towards the 4 minute mark then I'd say a P45 non plus would be a fine choice - if you're often towards the 8 minute mark then you probably need to anti up for a plus unit. This statement is very dependent on temperature though - if it is significantly colder than 64F then the back will do much better - if it's significantly warmer than 64F then it will do much worse.
Make sure you process in Capture One as it does a much better job than Lightroom/Aperture regarding long exposures.
-
a P25+ shooter has told me that with long exposures, the back requires the same length of exposure time to be ready to shoot again. Is there any true to this?
Correct.
-
Doug:
Thanks for your quick answer. As usual, it seems the final decision is up to oneself. Nevertheless, it was very useful.
Jon:
I use very little added light or none at all. I've found that I usually like best my pics this way. Ambience it's better preserved. The drawback is noise build-up and sometimes blurred people, which I happily trade. I know this fellow photog that owns a Nikon D3s. He says this camera completely changed his workflow. I own a 5D2 which is not bad either.
Best
Eduardo
Chris,
I wonder the same thing. I'm in the same boat as you. I dont see any use for long exposures in architectural photography unless for some reason you are trying to capture blurred clouds at dusk.
Eduardo,
You must use very little lighting, if any.
-
Correct.
Remember if you do a 15 min exposure time on a P45+ with a Tech Camera you will need to make a LCC shot.
1. Image exopsure - 15 min
2. Black frame - 15 min
3. Lcc plexi shot - 15 min (you can go up in ISO from 50 to 200/400 to get the same exposure)
4. Black frame again 15 min
Total time 1 hour for 15 minutes exposure on a Cambo/Alpa/Sinar/Arca shifted
Try to do stitching
Yes, you can have a library of LCC files, but the best LCC is always made on location IMO
-
Remember if you do a 15 min exposure time on a P45+ with a Tech Camera you will need to make a LCC shot.
1. Image exopsure - 15 min
2. Black frame - 15 min
3. Lcc plexi shot - 15 min (you can go up in ISO from 50 to 200/400 to get the same exposure)
4. Black frame again 15 min
Why does the LCC shot have to be a long exposure? The cast doesn't change with exposure time, it's only angle (and aperture and focus distance if one is very critical) dependent. Reducing the LCC exposure will also avoid the need for a companion Dark frame. In astronomy the so-called Flat field exposure is also a short exposure procedure.
Cheers,
Bart
-
Why does the LCC shot have to be a long exposure? The cast doesn't change with exposure time, it's only angle (and aperture and focus distance if one is very critical) dependent. Reducing the LCC exposure will also avoid the need for a companion Dark frame. In astronomy the so-called Flat field exposure is aslo a short exposure procedure.
Cheers,
Bart
Very simple if you are doing nightshots at avalible lights - this is the light avalible for the LCC file....
The plexi takes about 2-3 stops, so you would have to have even longer exposure times for the LCC file, but you can go up in ISO.
Alternative is to bring an external lightsource for the LCC file.
-
I'f I'm doing a dusk exterior, I'll try to make sure to grab an LCC exposure before the light drops, otherwise I go inside and shoot it near a bright wall.
Recent tip from another Arch shooter... an Expo Disc works as well as the supplied plexi for LCC's and you can fit in between the handles of a Cambo lens, which the standard unit will not.
-
Alternative is to bring an external lightsource for the LCC file.
bring a small handheld strobe and problem is solved.
-
bring a small handheld strobe and problem is solved.
Yes, I have discussed this option with the software guys at Phase, and they say this method could change the color balance and give a wrong reading, they prefer to go up in ISO with the same lightsource as the shot.
However I also bring a small strope.
I also have a complet library of LCC settings for every Camera setting and every lens on my Cambo. I will make notes on the Camera setting when shooting and use my library for LCC.
-
I'f I'm doing a dusk exterior, I'll try to make sure to grab an LCC exposure before the light drops, otherwise I go inside and shoot it near a bright wall.
Recent tip from another Arch shooter... an Expo Disc works as well as the supplied plexi for LCC's and you can fit in between the handles of a Cambo lens, which the standard unit will not.
Yes, I do so myself, buy you might have more than one shot.
Thanks for the Expo Dish tip - I will check this out, should perhaps be the flat one they use for video.