FS5 - dust and droplets

[Nigel Davey]

I seem to be plagued by dust and dried water droplet stains showing up on FS5 footage more than any camera I'ved previosly used. Is it just bad luck or is anyone else getting the same?

Incidentally I do clean my lenses and the glass in front of the FS5 sensor regularly. At least as regularly as I've always done.

[Noa Put]

Do you mean dust on the sensor? And where do the dried water droplet stains appear? Dust can get on a sensor but water?

[Nigel Davey]

Sorry, I should have been more clear. Yes dust on the sensor (or glass in front of) and water/dust on the lenses. Obviously the lens will receive as much water/dust as it would on any other camera. It's just seems blobs and blotches show up on my FS5 footage more than any camera I've had (or noticed before). Mostly on bright skies.

[Doug Jensen]

All of the e-mount cameras are more susceptible to getting gunk on the sensor because it's barely recessed into the camera body at all. Even though I did have to clean my A7s yesterday, I've never had to clean my FS7 in the year and a half that I've owned it and I change lenses all the time. I've never cleaned my FS5 so far either.

Are you careful to have the camera titled down when changing lenses? Do you have the next lens already sitting right next to the camera so there is maybe only a 3-4 seconds where the sensor is exposed? Are you careful to shield the camera from the wind?

Also, even if the sensor is filthy you shouldn't really see it in your shots unless you are shooting at a small aperture, maybe f/8 - f/16. I almost never shoot anything that isn't f/4 or faster. One reason I shoot almost wide open all the time is because I think the camera performs better at larger apertures, but a side benefit is that it really makes any little specks that may have gotten on to the sensor totally disappear. So make sure to use those ND filters and get in the habit of keeping your aperture at f/4 or faster and you might not even see dirt if it is there.

Cleaning lenses constantly is also overrated. Unless you are shooting into the sun or a bright light source you can have a lot of crap on the lens before it will show. It really doesn't make a big difference. I'll only clean my lenses when they reach a certain threshold of uncleaniness which usually takes weeks or months unless I'm shooting near the ocean or something where there is spray. And then I would only use proper lens cleaning paper and fluid which is alway in my camera bag just in case.

[Noa Put]

I always use a arctic butterfly to clear any dust from the sensor before every shoot and I always check the lenses for any dirt and clean if necessary, also before every shoot. I also do like Doug suggested to keep the front of the camera down so the sensor is facing down as well and have a second lens ready next to it so the sensor is only exposed for a few seconds. Having dust on your sensor can ruin your footage so I always very carefully check and clean.

[Cliff Totten]

The FS5's sensor is "sealed" behind a glass that protects the moving ND filter. I cant say that it's really "sealed" because it's hard to tell how tight that top glass is set into the plastic frame.

Can dust get under that glass? Can dust get sucked into the sensor cooling vents?

If I had to only guess, I'd suspect it's just that protective glass that need to be cleaned. I'd be careful though, it does seem to be a heavily coated glass. (probably to reduce flare/glare/artifacts)

I do remember Sony's Joseph Schmizzi talking on video about Sony taking an Arri design idea and encasing the FS5 sensor "inside" the heat sync to keep out environmental elements. (I'll try to find that video)

You have "blotches" and "blobs"? Sometimes lenses get mold growth but I have never heard of a sensor's getting them. I have a hard time believing that.

This happens with ND off?

What happens when you change lenses?

CT

[Doug Jensen]

I think it is pretty much understood that anytime someone talks about cleaning the "sensor" on any camera they are actually talking about cleaning the glass in front of the sensor.

[Cliff Totten]

What's that Doug???

If you are cleaning the "sensor" on, let's say an A7s, you are directly cleaning the surface of the sensor, or specifically, it's low pass filter bonded to its top surface.

However, the FS5 and FS700 has a glass plate, then the moving ND filter mechanism and the actual sensor is behind all of that. So, the FS5's glass surface plate is there to protect the ND filter mechinism. (I would certainly treat it with the same care though)

The FS5 glass plate is not the "image sensor" you are cleaning like you would be doing on many other cameras.

You can scratch that protective glass without hurting the actual CMOS sensor chip one bit. (it protects the ND glass too from dust and scratches) I would hope that Sony makes that glass easily replaceable. It should be cheaper than replacing the actual image sensor chip that's mounted to the circuit board inside under all that.

So, "cleaning the sensor" on a DSLR camera is very different than cleaning the "protective surface plate" on an FS5.

Other camera image sensors have no protection and when you clean them, you are "physically" touching those extremely sensitive CMOS chips.

Nigel, have tried more than one lens with the FS5 and do you see the same thing? Is the lens you are using a zoom lens? If so, do the spots "move" location when you zoom or do they stay in the same place as the image changes?

CT

[Doug Jensen]

Okay, to clarify . . . . I think it is pretty much understood that anytime someone talks about cleaning the "sensor" on any VIDEO camcorder (this is after all a video forum so I didn't think I needed to be more specific -- the A7s and DSLRs are not video camcorders and are not or part of this forum) they are actually talking about cleaning the glass in front of the sensor.

[Cliff Totten]

The Sony FS100, VG10/20 and 30 are "video camera's" too. If you clean those video cameras, you can scratch those sensors directly too. Video camera's without ND assemblies don't usually need that protective plate. (not 100% sure but I don't believe BlackMagic or RED video cameras have those protective plates either but I could be wrong)

So it's not a DSLR vs "video camera" issue. Its more of a camera with "ND filter" or "no ND filter" that is the issue. The FS5 has one so it's image sensor it's definitely in a MUCH safer place than a non ND filter video camera. (ie. Sony FS100)

Nigel, getting back to the issue, how do clean that FS5 plate? I "think" it has a coating on it. I dont know if its a top coating or a bottom coating. If it's a top coating, "maybe" that coating is damaged? (just a guess.)

Can you upload a short sample?

[Nigel Davey]

So far the blobs/blotches all vanish if I clean either the lens or the sensor plate/glass. In both cases I use a lens pen (smaller version for the plate) however I use a blower first. With the plate I don't exert much pressure, being aware of the coating and not wanting to damage it.

The lens I get issues most with is the 18-105 kit lens (my other main lens usage is a Sony 35mm f1.8 and a Tokina 11-16mm f2.8 via a Speedbooster). Obviously the 18-105 shouldn't be prone to dust/stains more than any other lens. But having owned the FS5 for 4 months I've had more clips with blobs and blotches on them than any other camera and the 18-105 gets used 65% of the time (I do a lot of run and gun).

Finally, yes the blobs move if I zoom in so it will be the lens. But there have been times (fewer admittedly) when I've had dust, even a smear, on the plate. Don't ask me how, I'm as careful changing lenses on the FS5 as I've been with DSLR's (where I don't end up with blobs and blotches). I apply the fast and down rule.

One thing that has crossed my mind is whether it's just down to the shorter space between the FS5 sensor/plate and first lens element compared to other formats?