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09-30-2012, 01:32 PM   #1
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Expensive Pentax Liveview

Here's an interesting observation. Using the Pentax live view wears out your camera twice as fast (at least if it's shutter actuations that matter).

With live view, using remote control activation, the sequence is:
  • (mirror stays permanently out the way) - IR signal -> shutter closes for shot -> shutter opens and takes shot -> shutter closes having taken shot -> shutter opens for live view
Without live view, the sequence costs half as many shutter actuations. It is:
  • IR signal -> mirror goes up -> shutter opens and takes shot -> shutter closes having taken shot -> mirror goes back down
So my preferred option would have to be without live view, but on 3s delay (Pentax default), which makes:
  • IR signal -> mirror goes up -> 3s later shutter opens, and takes shot -> shutter closes having taken shot -> mirror goes back down
3s delay is enough to damp mirror vibration but half as many shutter actuations as using live view.

From what I gather other brands don't have such an expensive liveview. For example Canon doesn't do the double shutter thing. Meh, poor Pentax design.

09-30-2012, 01:41 PM   #2
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You know that is interesting, I've never really thought about the actual mechanics of the operation.

I wonder in real terms does it really alter the life expectancy of a camera or does technical advances or CBA kick in first.
09-30-2012, 01:47 PM   #3
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I really don't see how it could work any other way when using LV. In LV the shutter needs to be closed before the shot can be made, and as you are in LV, the shutter needs to open after the shot is made.

Maybe if the camera had a sensor with electronic shutter, but I don't know if the sensor in Pentax DSLR support that.
09-30-2012, 02:43 PM   #4
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Apparently it is different on other brands! Ie on Canon, the shutter action is not doubled.
  • Canon Normal mode is mirror up, shutter open, shutter closed, mirror down.
  • Canon live view is electronic sensor reset to start the exposure, followed by shutter closed, mirror down, mirror up, and shutter open to resume live view.
  • Some of the higher Canon models can skip the mirror movement, leaving just mechanical shutter operation once per frame.
Just smarter put together I think. Don't know about Nikon.

09-30-2012, 02:58 PM   #5
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if the canon action is as you say, then they are limited in the maximum shutter, making it more of a video capture as opposed to a shutter

the image quality will go down because reset of the image capture is not as clean when you start recording instantly afterwards. Also if they are doing it this way, it makes it possible to do flash exposure at maximum shutter speed, but I don't see that being advertised
09-30-2012, 03:17 PM   #6
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As Lowell pointed out, it seems like Pentax realizes that overall, most of your shots won't be with live view, and if a few extra actuations must be made for 100% clean images, why not? Highly doubt anyone is burning through their shutters life by firing individual live view shots back to back.(As Continuous firing would result in 2 for the first shot, 1 for the rest I presume)
09-30-2012, 03:30 PM   #7
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My shutter is safe, I hardly ever use LV.
I think that shooting kids sports in Hi continious with AFC, is more of a concern for shutter life. Not unusual for me to come home with 1k+ shots from a single soccer match.

Last edited by Ex Finn.; 09-30-2012 at 03:39 PM.
09-30-2012, 03:34 PM - 1 Like   #8
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QuoteOriginally posted by Nass Quote
Just smarter put together I think. Don't know about Nikon.
QuoteOriginally posted by Nass Quote
Canon doesn't do the double shutter thing
My [mirrorless] NEX-5 does double shutter, and it is essentially live view all the time.

It's not 'poor Pentax design' issue.

Sigh. Pentax always seems to get rushed to the executioner around here.

09-30-2012, 03:46 PM   #9
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Yeah I think we all use cams for different purposes. Ie I stack a lot, 100s of exposures, and LV has in the past been recommended me because it's thought less vibration prone (a problem with what I do), ie like mirror lock up. But I wondered about that and looked at what was happening, and I think not. In fact the 3s delay is the most sensible, albeit a little short (I gather you can set that delay incam in some brands?). I wonder if stuff like the NEX-5 will wear out quicker and have a lower lifespan if it always does double? Actually I do wonder if shuttercount really has any bearing, I was on some shutter count site the other days and some cams rated for 100,000 were i to the millions. That 100,000 figure that's quoted seems a bit arbitrary
09-30-2012, 04:42 PM   #10
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QuoteOriginally posted by Nass Quote
I was on some shutter count site the other days and some cams rated for 100,000 were i to the millions.
I think since most of those shutters are made by the same third-party manufacturers (eg Copal) what you see on shuttercount for one brand is probably true across a number of brands who in fact may use the same shutter but could simply have different formulas for rating shutter life.

Anyway, Wikipedia gives me faith in modern focal plane shutters. Shutter durability and reliability have been on the improve for a while, apparently...

QuoteQuote:
...over the last twenty years, most effort has gone into improving durability and reliability. Whereas the best mechanically controlled shutters were rated for 150,000 cycles[99] and had an accuracy of stop from nominal value (more typically 50,000 cycles at stop), today's best electronically controlled FP shutters can last 300,000 cycles and have no noticeable speed error.

Last edited by rawr; 09-30-2012 at 05:40 PM.
09-30-2012, 05:29 PM   #11
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100K is MTTF (Mean time to Failure); Its not a guarantee that it will fail at 100K.

My K5 has been with me for 2 years and I do a reasonable amount of shooting.
Its only at around 20K actuations, so it has 8yrs more to go going at the rate that I'm using it.
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