EOS SL2; discussion about possible EVF & pellicle mirror

[Crosswind]

Hi! Y'know there were rumors about the SL2 being officially revealed in August or September 2015, so this month could be our hot spot!

Since Canon has patents for implementing EVF and pellicle mirrors in a DSLR type body (which could be a possibility for the SL2), my question is; how can I clean the image sensor of such a camera? Since there's a fixed mirror unit, I cannot reach the sensor with cleaning swabs or the like. Is there some mechanic that allows me to do that (except Canon's integrated ultrasonic cleaning)?

Next question is about the light that travels through the system. There's one more barrier for the light to pass through (in comparison to conventional DLSRs)... and that's the semi-transparent mirror. So does say [1sec f2 ISO100] give me the same exposure result as any other conventional DLSR with the same setting, or will it actually be a bit darker due to the pellicle mirror? If not, I think the electronics have to compensate for the slight loss of light (in order to get the same result), which amplifies image noise...

One more thing is, that EVFs can heat up the sensor over time, which leads to even more image noise (and it's a burden for the battery).

As a long time user of cameras with optical VFs, I'm pretty sceptical about this fixed mirror & EVF tech. As always, there are advantages and disadvantages...

 

[privatebydesign]

Re: EOS SL2; discussion about possible "pellicle mirror"

You don't need to clean the sensor, the dust can't get past the mirror.

The bigger issue is that pellicle mirrors have needed to be silvered on the outside, so cleaning them is very difficult to impossible, so much so that the 1NRS used to have a mirror replace as a near standard service item, it wasn't too expensive then either I seem to recall.

The sensor sees less light than there is, so if you have two cameras, SL1 and a pellicle SL2, then the exposures will be different for the same scene, that is, if the mirror costs you 1/3 stop of light a setting might be SL1 1/250, f4, iso 400, for the SL2 it could be 1/250, f4, iso 500, or 1/200, f4, iso 400 etc.

 

[Crosswind]

Re: EOS SL2; discussion about possible "pellicle mirror"

pellicle mirrors have needed to be silvered on the outside, so cleaning them is very difficult to impossible

When cleaning the sensor of my EOS 6D, I always used a dust-sticking brush with an adhesive rubber - which is a fast and good alternative for sensor cleaning IMO. Would this cleaning method be problematic for pellicle mirrors (as I don't want to damage the super-thin surface)?

edit; most lenses that I own are fixed-focal and so I'm changing lenses pretty frequently on my DSLR. This seems to be a problem on the long run for cameras with a pellicle mirror, right.

 

[privatebydesign]

Re: EOS SL2; discussion about possible "pellicle mirror"

pellicle mirrors have needed to be silvered on the outside, so cleaning them is very difficult to impossible

When cleaning the sensor of my EOS 6D, I always used a dust-sticking brush with an adhesive rubber - which is a fast and good alternative for sensor cleaning IMO. Would this cleaning method be problematic for pellicle mirrors (as I don't want to damage the super-thin surface)?

edit; most lenses that I own are fixed-focal and so I'm changing lenses pretty frequently on my DSLR. This seems to be a problem on the long run for cameras with a pellicle mirror, right.

For Canon pellicle mirrors up to date yes using a sticky brush would not be a good idea. Having said all this the tech could well have moved on since 1995! I thought one patent showed a back mirrored mirror so maybe that issue has been overcome.

 

[Mt Spokane Photography]

The SL will not change its basic design, Canon does not do that. They make incremental changes to new models, updating things like USB, Wi-Fi, GPS or other potential features.

A pellicle mirror camera would have a new model number, but don't hold your breath. The three previous pellicle mirror cameras did not sell. Canon is not likely to do it again.

 

[moreorless]

I don't really see much point on an SL2 personally, you still need to keep the AF sensor and its not like the prism/viewfinder is that large anyway?

It would actually make a lot more sense on a cheaper FF camera I'd say, there your at least looking at the potential of replacing a much larger prism/viewfinder with a smaller EVF. The height of the camera could probably be reduced a good bit that way, maybe slim down the grip a bit as well and your not far off the A7 mark 2 bodies.