Severe artifacts or noise problem with Phase IQ180

[dougpeterson]

Also if you're using zero latency the back could simply be hot. Switching to normal latency or turning the back off every once in a while (e.g. when moving to a new shot) would solve that issue. Usually doesn't matter for ISO35 and 1 second exposures, but we don't know the ambient temperature or how long the back had been on so I'm offering it as a variable to look into.

 

[Ztacir]

I thought about the reflections off the wall but apparently it is not the issue because it was a painted wall .However,I will perform the test "Popfoto" suggested.
I think what Doug is suggesting might solve my problem.This shot was taken some time ago but I have taken at least 100 shots and I have never turned off my back and it was August around 90's .
I will do some more tests and let you know the results .

 

[dougpeterson]

Make sure your IQ firmware is up to date. They made big improvements to power/heat management after the early firmware.

90's with the back on constantly in zero latency, or shooting many frames in a row without pause, would cause higher than usual noise in 1 sec exposures.

I notice this with people who bracket long expsoures. If you do a 30 second, then 15 second, then 8, then 4 seconds, then 2 second exposure, and you don't have any break between the images, then the last image will have noise similar to a 1 minute exposure since at the end of the 2 seconds the sensor will have been on and heating up for 59 seconds worth of exposure.

Not much time is needed for the back to dissipate heat away from the sensor. The passive cooling of the chassis is really excellent (great heat sink design). A very short break in shooting is all that's needed (if in normal latency) or a very short time of the back being off (if in zero latency). And no concern/adjust-to-workflow is needed at all if you aren't combining warm/hot weather with long exposures or high ISO.

 

[GrahamWelland]

Further to Doug's observation of the heat sink performance and zero latency, a friend of mine was shooting with his IQ & Credo backs recently under desert sun conditions (115f) and within 10-15 minutes or so the backs were HOT. Not hot, HHHOOOTTT to the degree that you could hardly touch them. I suppose that it's a testament to conducting heat away from the sensor and electronics passively but we were both surprised at just how blisteringly hot these backs can get.

Note to Phase One/Leaf: how about a white or reflective paint version? These backs both absorb and dissipate a lot of heat.

 

[jlm]

i also had a heat problem, running zero latency, apparently I had mis-set the auto-turn off time, (usually at 5 min) put the camera back in it's padded bag, and later found it HHOOOTTT

 

[gazwas]

While heat is a big culprit of hot pixels and 100 shots in hot conditions without a break is not great on a MF back, I also think a major part of it is to do with how much you pull the files about. By that I mean big LCC corrections for movements with tech lenses, pulling up exposure for badly exposed images or being too heavy handed lifting the shadows. A mixture of all three spells disaster and can really exaggerate this sort of problem and without knowing the original and your processing steps its tough to put it down to one reason.

Images posted below are original full version, 400% crop and 400% crop with the shadows over lifted. All with no noise correction applied and default sharpening on a P65+. As you can see the white pixels are visible in the original 400% crop but of little significance. With a bit of contrast/pulling up of the black levels they would virtually disappear. Pull up the shadows too much and the white pixels really stand out.

Shot at 0.5 sec at f11 with a SK43XL (no centre filter) and LCC correction in C1. Longer exposures just get worse.

 

[wentbackward]

Looks a heat problem to me. Had the same experience when my release cable failed and I had to use zero latency in the summer heat of HK/Thailand. Turning the back off for a bit works, they cool down really quickly.

 

[pophoto]

Further to Doug's observation of the heat sink performance and zero latency, a friend of mine was shooting with his IQ & Credo backs recently under desert sun conditions (115f) and within 10-15 minutes or so the backs were HOT. Not hot, HHHOOOTTT to the degree that you could hardly touch them. I suppose that it's a testament to conducting heat away from the sensor and electronics passively but we were both surprised at just how blisteringly hot these backs can get.

Note to Phase One/Leaf: how about a white or reflective paint version? These backs both absorb and dissipate a lot of heat.

You did say 115f heat, under those conditions, I would surely have melted by then, surely the back getting hot is "normal," no?

 

[GrahamWelland]

There's hot and then there's SCORCHING hot. Like John, he'd turned off the auto power off and it just got hotter and hotter.

Dry 115f - no problem. 80f and 99% humidity and you can keep it!

 

[LonnaTucker]

90's with the back on constantly in zero latency, or shooting many frames in a row without pause, would cause higher than usual noise in 1 sec exposures.

I notice this with people who bracket long expsoures. If you do a 30 second, then 15 second, then 8, then 4 seconds, then 2 second exposure, and you don't have any break between the images, then the last image will have noise similar to a 1 minute exposure since at the end of the 2 seconds the sensor will have been on and heating up for 59 seconds worth of exposure.

In reference to the above from Doug Peterson.

I am a Leaf user, but since the Phase IQ backs now use the Dalsa sensor that Leaf uses, a long exposure technique that Yair Shahar taught me to reduce hot pixel noise may be helpful and worth a try.

Try a very short exposure following each long exposure. For example, shoot at 1/500th after a 4 second exposure. Somehow the quick exposure helps to flush out the buildup of hot pixels. It won't completely eliminate them, but it is much better than shooting 8 sec several times in a row, or a series of long exposures brackets.

I live in the desert and over half the year we have temps in the 90's - 110's even at dusk. I do well with my Leaf Aptus, but the thought of upgrading to one of the new backs with the battery contained inside the back is a bit scary. I may be sticking with Aptus for now, as the new backs do get alarmingly hot!

However, I think it's kind of silly to setup up in direct sun at such extreme temperatures as 115F. A simple umbrella to shade your camera and digital back is easy enough to carry and use while shooting or waiting for the light, etc. and also is handy as a wind break during long exposures.