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

Audii-Dudii

Active member
I finally put my Contax/P30+ combo into service tonight with an outing to Miami, Arizona for some nighttime photography. Unfortunately, the initial results are not very promising, as (IMO) the images started to become excessively noisy after just 45 seconds of exposure at ISO100. (I also had some problems with the Contax 35mm lens creating ghosts whenever there was a strong light source in or just outside of the frame, despite using a lens shade and despite using a gobo to further shade the lens from direct light as much as possible. But I digress...)

The ambient temp was in the low to mid-80s range and according to Capture One's handy chart, the back should have been good for exposures as long as several minutes at these temps. But either my tolerance for noise is lower than for most people or my back isn't performing up to snuff, as the noise levels I experienced with tonight's batch of images are clearly excessive.

Anyway, while I wasn't planning on upgrading to a P45+ just yet, if it's a much better performer than the P30+ for long exposures, I may need to look into this as I fear the alternative may be for me to punt on medium-format digital and (don't laugh!) return to the various m4/3 setups with which I have been surprisingly successful previously. :eek:
 

Jack

Sr. Administrator
Staff member
What raw converter were you using, and what were the NR settings? You should have had very little noise at 45 seconds.
 

Audii-Dudii

Active member
Did you have a filter on the Zeiss 35mm?

-Marc
Nope. The scenes I photograph are illuminated by streetlights, so this has been a problem before with other lenses, but not to this extent. Usually, so long as I can block the light from the streetlight overhead from striking the lens, ghosting isn't a problem, but not so with the 35mm lens. I didn't compare them back to back, but I did briefly use the 45mm lens as well and didn't have any problems with it.
 
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Audii-Dudii

Active member
What raw converter were you using, and what were the NR settings? You should have had very little noise at 45 seconds.
I am using the latest version of C1 but I don't recall the NR settings off the top of my head and am at my office right now, so I can't check on this until I get home later today. I will admit to being very new to C1 -- I only started using it earlier this week! -- so maybe I'm doing something wrong (or at least not optimally) there? Oh, and the back has the latest version firmware installed, too.
 

Guy Mancuso

Administrator, Instructor
I'm a bit surprised by this . I had the P30+ do up to 35 minutes. Sure some noise but was pretty minimal. Now that was in cooler weather. Question how warm was the back to start with. I reside in AZ as well and right now a cam just sitting in the car for 10 minutes is deadly hot. Now the P30+ has micro lenses and the angle of the street lamps could possible be ghosting with a wide lens. That is very possible IMHO.
 

Jack

Sr. Administrator
Staff member
Re ghosts: One problem with older lenses before digital was rear element coatings. With digital, you get more reflection off the sensor glass back toward the rear lens element than you did with film. This can show up as fairly prominent ghosting when these lenses are used with digital, especially when strong, point-source light is in the frame. Newer generation lenses have been designed to help attenuate this. Of course filters, especially un-coated ones, can cause a similar effect from the front element bounce-back too.

Re noise: That's a weird one. Can you post an example of the image with excessive noise at 45 seconds, full frame and a crop of the bad area?
 

Audii-Dudii

Active member
I'm a bit surprised by this . I had the P30+ do up to 35 minutes. Sure some noise but was pretty minimal. Now that was in cooler weather. Question how warm was the back to start with. I reside in AZ as well and right now a cam just sitting in the car for 10 minutes is deadly hot.
Your comment about temperature has caused me to ponder a bit. Although last night was my first formal outing with the Contax/P30+ combo, I've used it several times before around my neighborhood as I was getting to know it, and the ambient temps on those occasions have all been in the upper 90s and the back became noticeably warm to the touch in use -- hot, even -- yet I don't recall having any significant noise problems then. That said, though, those exposures were all in the 10-30 second range, which is consistent with my experience last night.

I don't recall the back getting anywhere near that warm last night, but due to some operational issues I was having with focusing and composing images in the dim light, I was forced into composing and focusing images iteratively by tweaking the camera position and focus distance by reviewing the prior image on the LCD, which meant in some instances, I was banging off images more-or-less consecutively for 15-20 minutes as I homed-in on the final image. So even though the exposures were only 45-120 seconds long, the back was on (although idling at times) for a much longer period of time. Prior to this, I was turning off the back between images to keep it cool, but these were also the shorter exposures, so I'm not sure I can separate the effects at work here without some further testing / analysis.

Oh, and I apologize for starting this thread without posting any images to illustrate what I mean. It was sort of a knee-jerk reaction at the end of a disappointing evening and I'm now away from my home computer and don't have access to them ... doh! <*smacks forehead*>

Now the P30+ has micro lenses and the angle of the street lamps could possible be ghosting with a wide lens. That is very possible IMHO.
Hmm ... I hadn't thought of that. Interesting...
 

Audii-Dudii

Active member
Re ghosts: One problem with older lenses before digital was rear element coatings. With digital, you get more reflection off the sensor glass back toward the rear lens element than you did with film. This can show up as fairly prominent ghosting when these lenses are used with digital, especially when strong, point-source light is in the frame. Newer generation lenses have been designed to help attenuate this. Of course filters, especially un-coated ones, can cause a similar effect from the front element bounce-back too.
I realize that Contax / Zeiss lenses were designed before digital backs had become common, but they definitely existed at that point in time and surely Zeiss considered this factor in spec'ing its coatings? In any event, prior to buying into the Contax system, I searched the 'net rather thoroughly looking for info about the performance of the lenses -- scoured it, even! -- and I can't recall anybody, anywhere ever mentioning this as a problem with the 35mm lens. That said, I'll admit the type of photography I do is a bit unique, so it's certainly possible that I'm the first person to ever use it in precisely this manner ... who knows?

Re noise: That's a weird one. Can you post an example of the image with excessive noise at 45 seconds, full frame and a crop of the bad area?
Um, yeah. That was a bit of a bonehead manuever on my part, wasn't it? When I get home later today, I'll post some examples.
 

Jack

Sr. Administrator
Staff member
I was banging off images more-or-less consecutively for 15-20 minutes as I homed-in on the final image. So even though the exposures were only 45-120 seconds long, the back was on (although idling at times) for a much longer period of time.
This probably explains it as the heat build-up on the sensor is somewhat cumulative without adequate downtime between frames. I would guess what you were seeing is equivalent to the noise generated with a 15 minute or so exposure because of this; and 15 minutes at 80 degrees would be pretty noisy I think...
 

Jack

Sr. Administrator
Staff member
I searched the 'net rather thoroughly looking for info about the performance of the lenses -- scoured it, even! -- and I can't recall anybody, anywhere ever mentioning this as a problem with the 35mm lens.
Well maybe... But I owned and shot Contax MF, including the 35mm lens, for several years with film before Kodak released the DCS Pro back for it. I recall occasional ghosting in direct light conditions with that camera and digital back that I never noticed with film, but then I am older and it was a long time ago, so maybe my memory is flawed. Regardless, if it was due to the microlenses on your P30+ back, I would think the image of Guy's above would show it with the car lights in the frame...
 

Audii-Dudii

Active member
This probably explains it as the heat build-up on the sensor is somewhat cumulative without adequate downtime between frames. I would guess what you were seeing is equivalent to the noise generated with a 15 minute or so exposure because of this; and 15 minutes at 80 degrees would be pretty noisy I think...
Having slept on this overnight, this was one of the explanations I've come up with as well, which raises the obvious question as to how much downtime between exposures is necessary for low-noise performance? It looks like I'll need to do some more testing, especially as I typically bracket my images in groups of three, which means even shorter exposures will require the back to be on for several minutes at a time.
 

Guy Mancuso

Administrator, Instructor
Well general rule at least for me is if you feel warmth on the bottom of the back than turn it off before doing a long exposure. If your running them constantly your just building heat and in 80 degrees this will be even harder since the back will get warm after the first 15 minute shot. They simply will build heat. In cooler weather this is not a issue since it rarely will get warm but when you hit the 80 mark it almost pays to go for one than turn it off for awhile and cool the back down.
 

Guy Mancuso

Administrator, Instructor
LOL ... you have posted this photo before and it was definitely one of the factors that pushed me to buy a P30+. So, in a roundabout way, I guess this means I can blame you for putting me in this situation? :p
LOL been blamed for a lot worse. :D

Guess i emptied a few bank accounts along the way as well. Such a devil:ROTFL:

But seriously the P30+ is a great back no question about it and even though it maybe rated to a hour and in cold weather it maybe . I found 35 minutes in 55 degrees pretty good. Not sure I personally would push it further and I have seen Jack go the full hour on the P45+ the same night and he had awesome results
 

stephengilbert

Active member
"I have seen Jack go the full hour on the P45+ the same night and he had awesome results?" Do you bring chairs, or sit in the car?
 

Guy Mancuso

Administrator, Instructor
From hotel balcony . LOL


I should add C1 is your answer also with long exposure noise control now in version 5 and also working with luminance and color noise controls you can really get awesome results.
 
E

espressogeek

Guest
I haven't owned a Phase back on a while so I don't remember if the dark frame is automagic. Is the 30+ exposing a dark frame to subtract at the end of the exposure? I used to shoot a P21, non plus, for 35 minutes at a time with awesome results.
 
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