PaulB wrote:
It's quite obvious that most (none?) of you guys have used a 1nRS.
You really cannot tell that there is any light loss through the system at all, everything works fine, big, bright VF (infinitly better than 90% of modern DSLRs) and if you set ISO200 on a hand-held meter and transfer the reading to the camera it works fine and gives the same correct exposures as the camera metering.
Dust sealing would be of enormous value on a DSLR with a pellicle mirror.
Being able to see ALL the time is wonderful when doing action or flash.
The full 10fps on the 1nRS is only achieved by setting the 'On' switch to RS, when you half depress the shutter button the shutter is cocked - and exposure metering and AF are LOCKED at that point. Therefore during the 10fps burst the AF will NOT track and light changes not adjusted for. I rarely use the 10fps RS mode anyway as the 6fps' normal' shooting rate is fine most of the time - to be honest since I went digital I rarely use the RS at all, can't even remember the last time I shot on film..................... ...Show more →
Oh ya? Install the ec-r screen into a normal 1n camera and look through the viewfinder side-by-side. See if there's any difference in brightness
Pellicle mirror in the RS does block the light, so there IS light loss. I like the RS as much as the next guy, but it does cut the light to both viewfinder and film/sensor. This will remain the case until maybe some electro-chromatic mirror is designed for the camera.
BTW, how does the fixed mirror "seal" the dust? If anything, it will make cleaning the sensor next to impossible, but it does not seal of the shutter side of the mirror box, so how does it provide the "enormous value" of dust sealing?
If you mean that the mirror is in fixed position and thus doesn't bump dust around, keep in mind that the submirror still moves, so do the shutter curtains, so there's enough turbulence to move dust around.
Beni wrote:
Sure canon are about to kill their entire 5D line, only out 6 months, with a 3D. FYI the EOS 3 replaced the EOS 5, it didn't run in tandem.
I'm sure the rest of the rumour has as much credence.
That's not to say that a 3-series and 5-series couldn't run in tandem this time around, though I'm wondering if there's a strong-enough market for so many full-frame high-dollar cameras at one time.
Maybe at the end of the year. No telling what Canon has up their sleeve. They're predictably unpredictable at times.
mt-m wrote:
Oh ya? Install the ec-r screen into a normal 1n camera and look through the viewfinder side-by-side. See if there's any difference in brightness
Pellicle mirror in the RS does block the light, so there IS light loss. I like the RS as much as the next guy, but it does cut the light to both viewfinder and film/sensor. This will remain the case until maybe some electro-chromatic mirror is designed for the camera.
Yes, maybe around a 50/50 split, not too far off of what today's 60/40 mirrors provide to the viewfinder. There's a stop loss in both directions - to the sensor and to the viewfinder.
BTW, how does the fixed mirror "seal" the dust? If anything, it will make cleaning the sensor next to impossible, but it does not seal of the shutter side of the mirror box, so how does it provide the "enormous value" of dust sealing?
If you mean that the mirror is in fixed position and thus doesn't bump dust around, keep in mind that the submirror still moves, so do the shutter curtains, so there's enough turbulence to move dust around.
I think he means that the shutter & sensor will be located in a sealed partition behind the main mirror, impervious to airborne dust (and presumably assembled completely dust-free, or as dust free as practical). Not sure about the secondary mirror. Depends on whether a redesigned AF system is used or not. Suffice to say that if there is one, it would also operate in a sealed environment.
I hope it is clear that I mean absolutely no disrespect to the original poster, it is just that in MY opinion the RS concept as described does not make a lot of sense.
While no viewfinder blackout is certainly an added benefit of the RS system, it was not the main purpose of the design. High frame rate was the target, and at the time the 1nRS was the fastest AF SLR on the market.
Assuming that frame rate is still limited by data throughput, what would be the benefit of pellicle mirror in a DSLR? EOS 1V HS already does 10 FPS with full-size quick-return mirror, that's probably why there was no 1V RS model.
Another thing is, that with high-resolution sensor is it really a good idea to put a piece of glass at 45 degrees angle in front of it? I don't know the answer, just thinking out loud...
Maybe one day the pellicle mirrors will be the standard in the DSLR design - I just don't think it's of practical benefit right now...
Obviously Canon engineers understand cameras a bit better than I do, and it's entirely possible that I'll be pulling my foot out of my mouth in a week or so
Michael,
Note please that I didn't say that the VF was as bright as a 1v/D etc. Just making the point that when you are using it you don't notice the light loss, and that it is "infinitly better than 90% of modern DSLRs" - the other 10% been the 1 series! As to the light loss to the sensor - no big deal with the excellent sensitivity and low noise of present Canon CMOS. If you like to run your images through at ISO3200 and still get underexposure I guess you're in a minority anyway.
Also the pellicle seals off the outside world from the shutter/sensor, which in turn is sealed from the back - unless you have a DSLR with a removable back? I accept that cleaning the sensor would be "difficult" but would it be needed often? Many people now like to send their DSLRs back to Canon for sensor cleaning anyway.
And there is NO sub-mirror on the rear of the pellicle,
Thanks for sharing the information. Folks that say they know something won't happen have been proven wrong many times and they never learn, it seems. Keep your head up!
PaulB wrote:
Michael,
Note please that I didn't say that the VF was as bright as a 1v/D etc. Just making the point that when you are using it you don't notice the light loss, and that it is "infinitly better than 90% of modern DSLRs" - the other 10% been the 1 series! As to the light loss to the sensor - no big deal with the excellent sensitivity and low noise of present Canon CMOS. If you like to run your images through at ISO3200 and still get underexposure I guess you're in a minority anyway.
Also the pellicle seals off the outside world from the shutter/sensor, which in turn is sealed from the back - unless you have a DSLR with a removable back? I accept that cleaning the sensor would be "difficult" but would it be needed often? Many people now like to send their DSLRs back to Canon for sensor cleaning anyway.
And there is NO sub-mirror on the rear of the pellicle, ...Show more →
Paul, if you still have your RS, take the lens off and look into the mirror box. Pellicle mirror is not really sealing anything - it takes more space than a normal mirror would, but the area behind it is not sealed by any means. At least that's how I remember it.
Also, there absolutely IS the sub-mirror - how do you suppose the AF and off-the-film sensors would operate in the RS without the submirror?
As for not noticing the light loss in the viewfinder - I agree, you get used to it. For example, I just installed the Ec-S screen (which is darker than normal) into my 1D and I don't notice the light loss anymore. That, however, doesn't mean it's not there.
Light loss to the sensor - well, importance of this is very subjective. Same case can be made for f/4 lenses VS f/2.8 lenses etc. It's vital for some and irrelevant for others.
I don't have the camera, but I think I saw the schematic somewhere - I'll look for it...
I really hope that Canon brings out another pellicle mirror camera within the next few years. But I doubt we will see one this year.
I own a EOS RT which uses the pellicle mirror, I've been using it over the last few months and its great! The viewfinder isen't that much worse then any of my other cameras, but having no mirror blackout is well worth a slightly dimmer veiwfinder.
As for loosing 1 stop of light from the lens, Its not that big of a deal with digital as you can adjust the ISO and use noise reduction software when dealing with higher ISO's.
If Canon did make a pellicle mirror camera I would buy one!
mt-m wrote:
Paul, if you still have your RS, take the lens off and look into the mirror box. Pellicle mirror is not really sealing anything - it takes more space than a normal mirror would, but the area behind it is not sealed by any means. At least that's how I remember it.
Probably wasn't sealed since there was no need to do so. Opening the film back would negate any advantage of sealing anyway. But the pellical design certainly allows for sealing behind the stationary mirror. And that would be good.
Also, there absolutely IS the sub-mirror - how do you suppose the AF and off-the-film sensors would operate in the RS without the submirror?
I wonder if such a camera, in digital application, could have a new AF scheme, with no secondary mirror. Of course, if the secondary mirror operates within a clean, sealed environment, it wouldn't matter.
As for not noticing the light loss in the viewfinder - I agree, you get used to it. For example, I just installed the Ec-S screen (which is darker than normal) into my 1D and I don't notice the light loss anymore. That, however, doesn't mean it's not there.
Light loss to the sensor - well, importance of this is very subjective. Same case can be made for f/4 lenses VS f/2.8 lenses etc. It's vital for some and irrelevant for others.
That is, or could be important. Losing a stop is significant to some - not to others. I'm fond of the clean images I get at ISO 800, but not so fond of ISO-1600. Useable, but certainly not as clean. Of course if this new sensor were to have improved noise characteristics, it could compensate for the lost stop.
Pellicle mirrors don't "solve" the problem of dust on the sensor. Sure, your sensor isn't going to get dust, but now you have to worry about dust on the mirror itself. There's other benefits too such as .006 second shutter lag, no viewfinder blackout, and virtually silent operation.
Currently, I believe the bottleneck in digital cameras is feeding all the information onto your memory card. Your buffer will fill up while you're writing to the card. With film on the other hand, as soon as you take the shot, it's done. No wait time to "write to film" and no buffers to deal with. Once we get around that bottleneck of writing to the card, the mirror flip might be the next bottleneck to deal with.
If they're bringing out a pellicle mirror with Digic 3, that could only lead us to believe that besides better high ISO performance, they can shove way more information down the pipeline to your card than they could with Digic 2.
Yes there is a submirror assembly but it is not on the back of the pellicle, it is in the bottom of the mirror-box at the rear.
No, the pellicle doesn't hermetically seal the mirror-box, but doesn't have to in a film body anyway - it could in a DSLR though.
The light loss to the sensor/VF if highly over-rated and "in practice" is of no consequence; certainly the VF is better than most Canon DSLRs short of the 1s and perhaps the 5D, whilst the loss to the sensor simply wouldn't be noticed by 99% of users "in practice".
There would be many advantages to such an arrangement in a DSLR - no loss of view whilst shooting is just one of them, going back to a flippy mirror came as a shock when I went digital!
PaulB wrote:
Yes there is a submirror assembly but it is not on the back of the pellicle, it is in the bottom of the mirror-box at the rear.
No, the pellicle doesn't hermetically seal the mirror-box, but doesn't have to in a film body anyway - it could in a DSLR though.
The light loss to the sensor/VF if highly over-rated and "in practice" is of no consequence; certainly the VF is better than most Canon DSLRs short of the 1s and perhaps the 5D, whilst the loss to the sensor simply wouldn't be noticed by 99% of users "in practice".
There would be many advantages to such an arrangement in a DSLR - no loss of view whilst shooting is just one of them, going back to a flippy mirror came as a shock when I went digital!
Paul, now you are talking about another mirror - the one that gets the image off the submirror and directs it to [off-the-film-plane flash metering sensor.]EDIT: (sorry, meant to say AF sensors)
The sub-mirror is in the same place as with normal camera, it is just actuated differently (motor vs spring, etc) In RS mode it just retracts, in normal mode it actuates.
SKPhoton wrote:
Pellicle mirrors don't "solve" the problem of dust on the sensor. Sure, your sensor isn't going to get dust, but now you have to worry about dust on the mirror itself. .
But dust on the pellicle mirror wouldn't cause the "dust problems" that we see with today's cameras caused by dust on the AA-filter.
Why? Because the mirror is a lot further away from the sensor than the AA-filter is. It would have a similar (though greater) effect to dust on the rear lens element.
Thats true Dave, that tiny microscopic peice of dust woulden't look like a big black dot on your images if it was on the mirror as opposed to landing on the sensor/AA Filter!
It would also be easier to clean the mirror too!
If they managed to increase the buffer that would be great, Imagine shooting say 10-15 f/ps with minimal shutter lag and a large buffer, You would need some really big cards!
"Pellicle mirror versions of any EOS Digital SLR are technically possible, but as you say, customer demand for them has not been overwhelming so far. I'm sure that Canon Inc. would consider them more seriously if more photographers started requesting them."
