Julian Thompson Posted June 15, 2009 Share #1 Posted June 15, 2009 Advertisement (gone after registration) If 1/4000 is the maximum speed of the shutter on the 8.2 can someone explain how the EV works? (I guess that's me also asking - does EV just control the shutter or is it electronically dealt with somehow?) Sorry if this is very obvious I'm still learning :-)) Link to post Share on other sites More sharing options...
Advertisement Posted June 15, 2009 Posted June 15, 2009 Hi Julian Thompson, Take a look here What happens if you add - EV to 1/4000 on M8.2?. I'm sure you'll find what you were looking for!
Jamie Roberts Posted June 15, 2009 Share #2 Posted June 15, 2009 Julian-- I'm not exactly sure what you mean by "EV", but yes, the M8 and M8.2 only have one auto mode, really, and that's "aperture-priority" based. In other words, you set the aperture and the shutter speed is selected based on the meter. There's also "auto ISO" which lets you shift ISOs up and down at the edges of exposure as well, or, in manual, lock in a set of aperture and shutter combinations in rapidly changing lighting. But both cameras are best used on Manual (where you can use the meter to gauge what you want to do...) Link to post Share on other sites More sharing options...
chris_livsey Posted June 16, 2009 Share #3 Posted June 16, 2009 If 1/4000 is the maximum speed of the shutter on the 8.2 can someone explain how the EV works? (I guess that's me also asking - does EV just control the shutter or is it electronically dealt with somehow?) Sorry if this is very obvious I'm still learning :-)) Sensible question. Meter a scene to obtain a shutter speed, ideally use a uniform area of tone, change the EV and you will observe that the indicated shutter speed changes. If you "max out" by using high ISO and open f stop to get 1/4000 then try to decrease the exposure using EV adjustment the speed will flash on and off indicating you are out of operating range. ( you could of course close down the diaphragm but we are forcing the error here) Bottom line : EV controls the shutter speed in A mode. BTW It is the ISO that is changed electronically. The base speed of the chip is 160 all others are "false" in that they are obtained by amplification electronically. Some cameras with "in-between" speeds obtain these using two amplifiers and in some cases this leads to those speeds being noisier than the adjacent ones using a single amplifier. I remember when cameras weren't computers with a lens. Link to post Share on other sites More sharing options...
marknorton Posted June 16, 2009 Share #4 Posted June 16, 2009 From your question, you may be asking whether by setting a negative EV compensation, you can trick the cameras into going faster than 1/4000. The answer is no. The camera uses the metered brightness, and the selected ISO and EV compensation to select the shutter speed required, and if that comes out faster than 1/4000, you're out of road and you'll over-expose. Link to post Share on other sites More sharing options...
Julian Thompson Posted June 16, 2009 Author Share #5 Posted June 16, 2009 From your question, you may be asking whether by setting a negative EV compensation, you can trick the cameras into going faster than 1/4000. The answer is no. The camera uses the metered brightness, and the selected ISO and EV compensation to select the shutter speed required, and if that comes out faster than 1/4000, you're out of road and you'll over-expose. Thanks everyone - that was it Mark - I wondered if something electronic could help. Was the 1/8000 useful then on the M8? I was out on a sunny day the other weekend trying to shoot at F2 and I think I did run out of road! Why did they get rid of the 1/8000? Was it the shutter upgrade thing? Link to post Share on other sites More sharing options...
yanidel Posted June 16, 2009 Share #6 Posted June 16, 2009 1/8000th is definitely very useful on a sunny day if you shoot wide open. In another thread I posted shots taken with the 60mm at F1.2 Many of the shots were at 1/8000th and still it was not sufficient in some cases and had some blown highlights (though I could fix most of it in post processing). So to me, the 1/4000th speed would be my main problem with the M8.2. Link to post Share on other sites More sharing options...
chris_livsey Posted June 16, 2009 Share #7 Posted June 16, 2009 Advertisement (gone after registration) Look at a ND filter to bring the speed back down. Link to post Share on other sites More sharing options...
marknorton Posted June 16, 2009 Share #8 Posted June 16, 2009 Why did they get rid of the 1/8000? Was it the shutter upgrade thing? Yes, it was the price to be paid for the quieter shutter. I haven't seen the new one but the old one has quite strong springs to make it work, the force required on the cocking lever to set it is surprising. The weaker the springs, the slower the shutter moves and the less noise and vibration - if you halve the speed of the shutter, the kinetic energy dissipated into the body shell is reduced by a factor of 4. The reason why that means no 1/8000 is because at that speed, the shutter is actually a slit moving across the frame; the slower the slit is moving, the narrower it has to be for a given exposure. Ball park, on the M8, the slit moves 18mm in 1/250 second so that for an exposure of 1/8000, the slit is about 0.5mm wide; in the M8.2 or M8u, the slit is even narrower and it becomes more difficult to set the slit width accurately to ensure both consistent exposures shot to shot and even exposure across the frame. Link to post Share on other sites More sharing options...
jaay Posted June 16, 2009 Share #9 Posted June 16, 2009 The loss of the 1/8000 shutter speed was a big reason i bought the M8 and not the 8.2 (price was the other!). I have also just purchased a 50 f1.4 asph and to ensure i can always shoot wide open outside in bright conditions i got a b+w ND 3-stop filter too. On my Canon 1DIII i often set the ISO to 50 to shoot at f1.2 in daylight. Link to post Share on other sites More sharing options...
jaapv Posted June 16, 2009 Share #10 Posted June 16, 2009 Yes, it was the price to be paid for the quieter shutter. I haven't seen the new one but the old one has quite strong springs to make it work, the force required on the cocking lever to set it is surprising. The weaker the springs, the slower the shutter moves and the less noise and vibration - if you halve the speed of the shutter, the kinetic energy dissipated into the body shell is reduced by a factor of 4. The reason why that means no 1/8000 is because at that speed, the shutter is actually a slit moving across the frame; the slower the slit is moving, the narrower it has to be for a given exposure. Ball park, on the M8, the slit moves 18mm in 1/250 second so that for an exposure of 1/8000, the slit is about 0.5mm wide; in the M8.2 or M8u, the slit is even narrower and it becomes more difficult to set the slit width accurately to ensure both consistent exposures shot to shot and even exposure across the frame. Not just that, Mark, you get diffraction in the slit too. Link to post Share on other sites More sharing options...
A Sfeir Posted June 16, 2009 Share #11 Posted June 16, 2009 Thanks everyone - that was it Mark - I wondered if something electronic could help. Was the 1/8000 useful then on the M8? I was out on a sunny day the other weekend trying to shoot at F2 and I think I did run out of road! Why did they get rid of the 1/8000? Was it the shutter upgrade thing? I think the 1/8000 was removed to decrease noise from the shutter (acoustic noise). I too love the new shutter but regret the 1/8000 particularly as I live in a sunny country, and like to use the superb new summilux wide angles with the shallow depth of field. I am getting ND filters for that. Link to post Share on other sites More sharing options...
yanidel Posted June 16, 2009 Share #12 Posted June 16, 2009 Look at a ND filter to bring the speed back down. UV/IR + ND starts to be a bit too much on a lens IMO. Link to post Share on other sites More sharing options...
marknorton Posted June 16, 2009 Share #13 Posted June 16, 2009 Not just that, Mark, you get diffraction in the slit too. Indeed... Link to post Share on other sites More sharing options...
chris_livsey Posted June 16, 2009 Share #14 Posted June 16, 2009 UV/IR + ND starts to be a bit too much on a lens IMO. At least I didn't suggest a starburst Link to post Share on other sites More sharing options...
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