Who needs the mirror?

[piiooo]

I was recently wondering if Canon comes up with a Panasonic Lumix G type of camera any time soon. Theycould replace the pentaprism/mirror complex with a high resolution viewfinderbutkeep everything elseas it isina DSLR,maintainingcompatibility with EF and EF-s Lenses.


I think the advantages among many would be: 1)no hassle live view 2)less moving parts - less things to brake3) less dust on sensor 4)lesser weight 5)ability to display more informationinviewfinder, or customize the viewfinder 6)100% viewfinder coverage


A potential disadvantage would be AF speed, I guess


What isyour take on the concept?

[Daniel Browning]

I was recently wondering if Canon comes up with a Panasonic Lumix G type of camera any time soon. They could replace the pentaprism/mirror complex with a high resolution viewfinder but keep everything else as it is in a DSLR, maintaining compatibility with EF and EF-s Lenses.

I would love that.

I think the advantages among many would be: 1)no hassle live view 2)less moving parts - less things to brake 3) less dust on sensor 4)lesser weight 5)ability to display more information in viewfinder, or customize the viewfinder 6)100% viewfinder coverage

Here are a few more advantages:

• Zooming to any part of the image for critical focus
• View the actual captured image, including white balance, black and white, etc;
• Tilt/swivel.
• Movie mode.
• Live zebras, histograms, false color "raw" mode, guide lines, overlays, etc.
• Accurate DOF (typical viewfinder screens show f/1.2 as if it were f/3.5, making critical manual focus impossible).
• Accurate rendition of the bokeh
• Usable in much darker situations, including effective f/32 for macro, etc.
• Contrast detect autofocus with movable focus points
• Allows the entirety of the primary mirror to be used for phase detect autofocus
• The possibility of reducing lag from 40ms to 0ms or even negative lag

Disadvantages compared to an optical viewfinder:

• Battery usage
• Heat generation (in rare circumstances can cause thermal noise to rise above the read noise floor).
• Dynamic range limited by the sensor instead of the eye/brain.
• More expensive
• Slow frame rate
• Low resolution
• Bulky

These will improve as technology progresses.

A potential disadvantage would be AF speed, I guess

Not necessarily. They could leave the mirror in (just remove the pentaprism and viewfinder), and use the entire mirror for autofocus. Right now the autofocus can only use a tiny central portion of the light from the partially transparent area of the main mirror. This limits the coverage of autofocus on full frame sensors, and the amount of light for low light autofocus.

If autofocus didn't have to play second fiddle to viewfinder, then all the light from the main mirror could be used for autofocus, with coverage over the full frame entire sensor, and better performance in low light.

Who needs the mirror?

There are many photographers for whom the current technology is too expensive or insufficient, even if it were built into the camera they need.

A $50 million feature film was shot with a $3k EVF using manual focus and thin DOF ("Knowing"; it grossed about $93 mil so far). They will only get better, smaller, and cheaper with time.

I think its inevitable that they appear in more and more cameras.

[piiooo]

A potential disadvantage would be AF speed, I guess

Not necessarily. They could leave the mirror in (just remove the pentaprism and viewfinder), and use the entire mirror for autofocus. Right now the autofocus can only use a tiny central portion of the light from the partially transparent area of the main mirror. This limits the coverage of autofocus on full frame sensors, and the amount of light for low light autofocus.

If autofocus didn't have to play second fiddle to viewfinder, then all the light from the main mirror could be used for autofocus, with coverage over the full frame entire sensor, and better performance in low light.

The video (link below) shows that fast AF is perfectly doable in this type of configuration


http://www.youtube.com/watch?v=HuPxftjjFHQ

[dmckinny]

OK, I'm obviously missing something here, EVF is electronic view finder (right?). So what is the difference between what you are talking about and the EVF on my old Canon Powershot S1 IS? Is it the same basic concept? Or are you talking about something completely different?





Just curious,


David McKinny

[piiooo]

OK, I'm obviously missing something here, EVF is electronic view finder (right?). So what is the difference between what you are talking about and the EVF on my old Canon Powershot S1 IS? Is it the same basic concept? Or are you talking about something completely different?





Just curious,


David McKinny
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The major differences wouldinclude APS-C or FF sensor and interchargeable, preferably EF/EF-S lenses.

[alexniedra]

1. "No Hassle Live View"


- Are you saying Live View in a DSLR is a hassle?


2. "Less Moving Parts - Less things to brake"


- Yes, shutters give out after tens, or hundreds of thousands of exposures, but I don't see this has a big shortcoming of DSLR's. My 40D will be obsolete before I take 100,000 shots.


3. "Less dust on sensor"


- With a shutter covering the sensor most of the time, wouldn't a DSLR have less dust? With the sensor constantly exposed, I wouldn't expect less dust on the sensor.


Also, the sensor would most likely have the tendancy to heat up more quickly. We can see this in DSLR's equipped with Live View. Live View will stop after a certain period of time beceause the sensor has to cool down.

[Daniel Browning]

Thanks for the response.

shutters give out after tens, or hundreds of thousands of exposures

Some photographers, like me, take 10,000 photos in a month. I'll do 5,000 in one weekend if I'm shooting timelapse. But I think we're a small minority.

- With a shutter covering the sensor most of the time, wouldn't a DSLR have less dust? With the sensor constantly exposed, I wouldn't expect less dust on the sensor.

I'm not sure. I've read that the air turbulence caused by a swinging mirror is what causes most of the dust. I don't think the sensor is "exposed" with liveview any more than with a mirror. The shutter can cover the sensor for lens changes just as well in both cases IMHO.

[Tim]

A digital viewfinder sounds like anawfulidea to me. when your eyes gets too close to a digital screen, its very easy to see pixels, and it might actually hurt your eye after a while. besides, I like mechanical devises way more than electrical ones.

[piiooo]

1. "No Hassle Live View"


- Are you saying Live View in a DSLR is a hassle?

Yeah, when you focus in live view/quick mode the mirror flips to focus. Disadvantage: noise and interrupted image. When you use contrast based AF, there is no flipping, but it takes sometimes a few seconds to get the image sharp. Plus - the overheating issue, i addressed it below.

2. "Less Moving Parts - Less things to brake"


- Yes, shutters give out after tens, or hundreds of thousands of exposures, but I don't see this has a big shortcoming of DSLR's. My 40D will be obsolete before I take 100,000 shots.

Just google for example: "canon 5d mirror recall"


I hope it won't turn into " canon XX markX vievfinder recall" in the future[]

3. "Less dust on sensor"


- With a shutter covering the sensor most of the time, wouldn't a DSLR have less dust? With the sensor constantly exposed, I wouldn't expect less dust on the sensor.

Like Daniel said, aflipping mirror produces turbulences inside camera whichstirs exogenous and endogenous dust in the camera.Because it usually happensjust beforethe shutter opens, the dustmay wind up on the sensor.

Also, the sensor would most likely have the tendancy to heat up more quickly. We can see this in DSLR's equipped with Live View. Live View will stop after a certain period of time beceause the sensor has to cool down.

Canon have been making camcorders including professional ones for quite a while, I hope they will use their camcorder technologies in their perspective cameras, just like Panasonic did.

[piiooo]

A digital viewfinder sounds like anawfulidea to me. when your eyes gets too close to a digital screen, its very easy to see pixels, and it might actually hurt your eye after a while. besides, I like mechanical devises way more than electrical ones.
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Each, mirror/pentaprism and electronic viewfinder have their pros and cons. IMHO, traditional setup will work better for sports/action/wildlife shooters, and the new one may appeal to still/landscape photographers. I hope to see both types of cameras available for a long time, although my prediction is that the electronic viewfinder will eventually take over.


As far as eye strain, if a good quality/resolution vewfinder is used, it is not worse than eye strain from using a traditional veiwfinder.