Long exposures and XF light tightness

[GrahamWelland]

I was wondering if any of the proud new recipients of the Phase One XF had tried proper long exposures with the camera and could comment on light tightness?

i've use the DF/DF+ for multi-minute exposures and it leaks horribly and needs gaffer taping/covering with a lens wrap/beanie hat for good results. I'm hoping that the XF is better.

anyone tried it? 120s + is the range I'm looking at.

This was DF/IQ160 until wrapped up (obviously eyepiece was covered already, this is the body):

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[Don Libby]

Graham, I remember doing lightning shots for several minutes shortly after getting the XF with my 180; of course it was dark so I didn't see any issues. Not near the studio but will look at what I have and share later.


Don

 

[GrahamWelland]

Thanks Don.

My problems were primarily in direct sunlight when shooting with ND filters. The leaks came from the back/body mount and also I believe the IR focus sensor too with the DF series bodies. Wrapping the body/back fixed it but there was the downside of keeping a very warm back super toasty in a wrap vs air cooled when shooting for extended periods.

 

[Don Libby]

Graham, you still in HK? How 'bout coming to the warm SW and I'll show you the XF.

Don

 

[GrahamWelland]

Alas I'm on the road in Asia until the 26th. Now if you happened to be in Tampa next week ... but I'd love to come by and check out the XF for myself.

CI are going to run some tests for me too they said.

 

[kdphotography]

... How 'bout coming to the warm SW and I'll show you the XF.

Don

Party at Don's! :ROTFL:

 

[ondebanks]

This was DF/IQ160 until wrapped up (obviously eyepiece was covered already, this is the body):

Looks like light coming in through the dark-slide slot.

Oh, wait....:grin:

I notice from that album that you also had to tape up your back when it was on the Alpa - so maybe it's not just a DF body issue.

Ray

 

[GrahamWelland]

Ray

Actually the Alpa tape up was due to an abundance of caution and it wasn't really necessary in the end. The DF seemed to leak via the Front of the body vs the eyepiece slide etc.

 

[Pelorus]

Graham,

Completely off topic, but what is the tripod plate on your STC in that shot please?

Regards
Mike

 

[GrahamWelland]

Graham,

Completely off topic, but what is the tripod plate on your STC in that shot please?

Regards
Mike

That would be the Really Right Stuff MPR-73 3/8ths mount. The horizontal bar prevents rotation and I have these on the bottom/side so that I can shoot the Alpa stc with shift or rise/fall easily.

 

[Pelorus]

Thanks Graham, and thanks also for how you stop rotation. We'll now resume normal programming...

That would be the Really Right Stuff MPR-73 3/8ths mount. The horizontal bar prevents rotation and I have these on the bottom/side so that I can shoot the Alpa stc with shift or rise/fall easily.

 

[Stuart Richardson]

Thank you for the post Graham. I am curious if your light leak issue is the same as a phenomena that I sometimes see on sensors that have been pushed very hard or underexposed. I have seen it on everything from my S2 to the Sony A7s. Basically, the edges of the sensor seem brighter and redder/more magenta than the rest of the frame...it usually does not occur unless the sensor is really stressed, such as underexposed and then pushed several stops. I always chalked it up to sensor noise, but now I am thinking that it could also be light leaking through the eyepiece or body. I have never really bothered to cover the eyepiece, as it never caused any obvious problems for me.
I am attaching an example. I just had gotten the A7s and was trying to see what it could do. It is a shot of my girlfriend taken only from the light of an aurora. It is with the 55mm at 1.8 for 1/8th of a second handheld, at ISO 160,000. I bumped up the shadows +70 points in lightroom. Clearly, this is stressing the sensor! It is not much of a photo, other than the fact that a photo is there, despite there being nearly no light. But there are these clear areas of reddish light around the edges...is this from light leaking into the camera, or is it just the consequences of pushing a sensor past its capabilities, like I had assumed?

View attachment 94461

 

[Shashin]

Thank you for the post Graham. I am curious if your light leak issue is the same as a phenomena that I sometimes see on sensors that have been pushed very hard or underexposed. I have seen it on everything from my S2 to the Sony A7s. Basically, the edges of the sensor seem brighter and redder/more magenta than the rest of the frame...it usually does not occur unless the sensor is really stressed, such as underexposed and then pushed several stops. I always chalked it up to sensor noise, but now I am thinking that it could also be light leaking through the eyepiece or body. I have never really bothered to cover the eyepiece, as it never caused any obvious problems for me.
I am attaching an example. I just had gotten the A7s and was trying to see what it could do. It is a shot of my girlfriend taken only from the light of an aurora. It is with the 55mm at 1.8 for 1/8th of a second handheld, at ISO 160,000. I bumped up the shadows +70 points in lightroom. Clearly, this is stressing the sensor! It is not much of a photo, other than the fact that a photo is there, despite there being nearly no light. But there are these clear areas of reddish light around the edges...is this from light leaking into the camera, or is it just the consequences of pushing a sensor past its capabilities, like I had assumed?

View attachment 94461

Stewart, I cannot see your attachment. The only time I get leaks in my camera, Pentax 645D, is when I have a very dense filter on, an NIR or ND. Basically, light leaks through the eyepiece. In this situation, the exposure through the lens is such that light leaking into the camera from other routes becomes significant. Without the filtration, the exposure through the lens should always be significantly greater than any possible leak. Unless you were shining a light on your camera without any going through the lens, I doubt the red is light contamination. If that were the case, you should be getting leaks no matter the ambient light situation.

 

[Stuart Richardson]

Thanks Will...I am trying attach it again. Your reasoning is basically what I was thinking, but then I was thinking that when you have a lens and shutter speed that reduce the light level reaching the sensor to the absolute minimum, perhaps some of the residual light getting through can have an influence...

 

[Shashin]

Stewart, that looks like sensor noise caused by heat, which is usually around the edges. This is what my camera looks like when it leaks light (through the eyepiece and passed the raised mirror). Notice the vertical line on the right of the frame and the flare. I have made a cap for my eyepiece. Camera leaks tend to be directional from a single source, rather than general.

You know photography is light dependent. Give your camera a break if you are shooting handheld with illumination from an aurora! ;-)

 

[Stuart Richardson]

You know photography is light dependent. Give your camera a break if you are shooting handheld with illumination from an aurora! ;-)

It was brand new...I had to break it in! Heat is another thing I had not considered, but I guess it could make sense....it was not exactly warm out there, however. I was doing video as well out there, so it is certainly possible. Thanks for pointing me in that direction. The light leak you showed is indeed much more of what I would expect, based on using film Hasselblads and Leica M's with malfunctioning shutter curtains etc. What I was thinking regarding the edges was that was seeping in through the cracks, like light under a door...

 

[mjr]

Stuart

I have shot hundreds of aurora with my S and definitely need the eyepiece cover, without there is a big issue but I don't think that shot is showing light leak, I have the same on shots I push hard as you suggested, it's like the edges and corners get a magenta cast, even in very cold temperatures, definitely more prominent on underexposed shots pushed in post.

For the S I have found a maximum of 6 seconds at ISO200 gives a lovely clear shot with very little noise and picks up the aurora very well, if I don't mind star trails then ISO100 will go for the maximum shutter speed with no issues, higher than ISO200 though and I don't really like the results.

This from last week, first aurora of the season, S with the 35mm wide open, 6 seconds at ISO 200 and no corner issues. Not very interesting shot as just from my garden but the S does very well as I'm sure you have experienced. I have shot lots of people under aurora and have found that lowest power on a flash unit hand held and fire it off before the end of the exposure gives a lovely light on people and captures the aurora overhead.