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03/20/2007 05:00:16 PM · #1 |
On my P&S camera, when I press the shutter button halfway, the brightness changes to what I'll get in the final image (or so it seems, anyway). So if the autoexposure is off, I can see it.
Is that not the case in DSLRs? I've been reading about how important various metering techniques are for those, but I'm a bit lost as to why it matters so much if you can see what's coming by pressing halfway. I mean, I just try it and adjust accordingly.
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03/20/2007 05:04:31 PM · #2 |
With a DSLR, one sees through the lens, not via the image sensor. Half pressing the shutter button locks focus (and, most often, exposure), but the view through the viewfinder will not, cannot, change. The only real preview (if you're not using a 1DIII) will be to press the DOF preview button if one has stopped down from wide open) to get an impression of what will be in focus.
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03/20/2007 05:11:07 PM · #3 |
| My K10D has the option of a "digital preview," which is basically just taking a photo without recording it on a flash card. Its only really useful when trying to get your white balance spot on, otherwise you might as well just take the photo and see what you need to adjust. |
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03/20/2007 05:12:29 PM · #4 |
Thanks, guys. I've read that before but I think I'm only now really beginning to understand it.
What I'm still wondering is why. What does not showing you what the sensor sees buy you? It must be better, but in what way?
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03/20/2007 05:14:53 PM · #5 |
doesn't buy you anything. It's just not possible with a DSLR to get a real time exposure preview.
Edit to add...
it does buy you the fact that you look through your lens to see your image and not a LCD screen. This is worth the loss of the exposure preview in my opinion.
Message edited by author 2007-03-20 17:17:03. |
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03/20/2007 05:18:00 PM · #6 |
Originally posted by levyj413:
What I'm still wondering is why. What does not showing you what the sensor sees buy you? It must be better, but in what way? |
It buys one a little more speed, in short (in general, at least). The optical viewfinder is miles faster than an EVF or LCD, as the two latter are bound by their refresh rate.
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03/20/2007 05:26:33 PM · #7 |
| It's a direct consequence of the SLR design. When you're looking through the viewfinder, the mirror is in the way of the sensor, reflecting the light up through the viewfinder. What this buys you is a direct view through the taking lens, something no other camera design offers... except digital P&S cameras. The "live preview" of digicams is one of their main benefits, but the low resolution of display screens limits the usefulness. You'd need a display of several megapixels to approach the quality of an optical viewfinder. Current displays are less than 100,000 RGB pixels. |
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03/20/2007 05:35:03 PM · #8 |
Oh, I agree about the quality of the electronic viewfinder - mine has one.
But I'm still left wondering why it matters. I mean, I don't need particularly sharp previews. Mostly I want to know whether I'm pointed in the right direction, what's behind my subject, and whether I'm zoomed appropriately.
Shrug.
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03/20/2007 05:46:23 PM · #9 |
Originally posted by levyj413:
Oh, I agree about the quality of the electronic viewfinder - mine has one.
But I'm still left wondering why it matters. I mean, I don't need particularly sharp previews. Mostly I want to know whether I'm pointed in the right direction, what's behind my subject, and whether I'm zoomed appropriately.
Shrug. |
Once you've become accustomed to an optical viewfinder it's painful as heck to use an EVF or rear LCD preview. It's near impossible to judge focus on either one, and with the narrower DoF of an SLR, especially at large apertures, that is a big deal. Even the difference between the typically-smaller viewfinders of APS-C DSLRs and the larger ones on 35mm DSLRs is significant. |
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03/20/2007 06:26:03 PM · #10 |
Ahhh. Focus! Now THAT makes a lot of sense, esp. with the point about much narrower DOF being available. That DOF issue is one of the things that bugs me most about my camera, along with poor low-light performance. And manual focus is so bad that I frequently use my camera's focus bracketing feature.
Thanks!
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03/20/2007 06:28:49 PM · #11 |
Originally posted by kirbic:
Once you've become accustomed to an optical viewfinder it's painful as heck to use an EVF or rear LCD preview. |
I agree. At a recent work conference, A co worker handed me a tiny little camera to take her picture. When i took the camera I put it up to my eye only to realize it didn't have an optical viewfinder. I looked like an idiot trying to figure out how to operate this tiny little camera. |
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03/20/2007 06:50:52 PM · #12 |
um....are you all forgetting the Olympus E-330? The first DSLR with LIVE PREVIEW?
Two sensors. One for the image in the regular SLR way. One for the live LCD preview.
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