What are the practical differences between DSLR and Sony SLT cameras?

Asked 4/28/2013

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I use a Sony SLT camera and want to better understand how it differs from a traditional DSLR in everyday shooting.

My understanding is that an SLT uses a fixed semi-transparent mirror, which allows live exposure preview in the electronic viewfinder/LCD and phase-detect autofocus to operate continuously. A DSLR uses a moving mirror and optical viewfinder, so the behavior is different, especially for live view and autofocus.

I’m particularly trying to confirm:

  • whether continuous AF on a DSLR works by lowering the mirror between shots in a burst so the AF module can keep updating focus
  • how DSLR autofocus changes when using live view
  • the main practical differences between an SLT’s EVF/live preview and a DSLR’s optical viewfinder

Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0

Photography Stack Exchange contributor

13y ago

2 Answers

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Short answer: the difference is in an SLR the mirror flips up to take a photo, whereas the SLT employs a semi-transparent mirror so that the mirror never has to move.

Now to your questions:

1) How does a DSLR do continuous focusing (AI servo/AFC)? Does it literally flip the mirror up, take the shot, put the mirror down, refocuses and repeat?

That's correct, assuming the DSLR is not in live-view mode.

If the camera has a live-view mode and that is turned on, then the mirror will stay up the whole time (and you won't see anything through the optical viewfinder at any time) and it'll switch to CDAF which is usually slower in a DSLR.

Wheras in the SLT camera it should be able to continuously use PDAF auto-focus while taking a shot or not.

2) How does a DSLR user account for the fact that the OVF has significantly greater dynamic range than the actual user? Do you just get used to it and compensate mentally?

Yes, you get used to it, just as you get used to judging the contrast of a scene with just your eyes - no camera at all.

Besides, even with cameras that have a live-view or digital viewfinder, you can't rely on the depth of blacks or contrast shown there to be indicative of the recorded picture - often sunlight, reflections and the relative quality of the LCD display make that hard. You still have to do some level of mental correction. There's also histograms and things that you can turn on.

Originally by user3422. Source · Licensed CC BY-SA 4.0

user3422

13y ago

0

AI Answer

Generated from our catalog & community — verify before relying on it.

The core difference is the mirror. A DSLR uses a moving mirror that flips up during exposure; an SLT uses a fixed semi-transparent mirror, so it doesn’t need to move for each shot.

In normal DSLR viewfinder shooting, phase-detect AF works while the mirror is down. During the exposure the mirror flips up, which blocks the dedicated AF sensor, so the camera cannot measure phase-detect AF at that instant. In continuous AF, it refocuses between shots, and some DSLRs also use predictive tracking to estimate subject movement during the brief blackout.

In DSLR live view, the mirror typically stays up, so the optical viewfinder is unavailable and autofocus often switches to slower contrast-detect AF.

With an SLT, phase-detect AF can remain available during shooting and video because the fixed mirror is always sending some light to the AF sensor. That’s one of the main practical advantages.

Viewfinder behavior is also different: a DSLR optical viewfinder shows the scene directly and does not give a live exposure preview, while an SLT’s electronic viewfinder can preview exposure, white balance, and depth of field more directly.

UniqueBot

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13y ago

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