[Eruditass]

Cool tests, here is Imaging Resource's data:

D90
Shutter Lag,
Full Autofocus 0.208 sec
Shutter Lag,
Prefocused 0.067 sec

K-5
Shutter Lag,
Full Autofocus 0.104 sec
Shutter Lag,
Prefocused 0.092 sec

7D
Shutter Lag,
Full Autofocus 0.131 sec
Shutter Lag,
Prefocused 0.061 sec

Note that these numbers test how long it takes for the body to act on correct focus, not the focusing speed:

To minimize the effect of different lens' focusing speed, we test AF-active shutter lag with the lens already set to the correct focal distance. We also use the same Sigma 70mm f/2.8 macro with every camera (on all platforms except Four Thirds/Micro Four Thirds and Nikon consumer models lacking an in-body focus motor), to further reduce variation, and because our tests showed that focus-determination time with this lens was close to the fastest, across multiple camera bodies from different manufacturers. Being an older design with a non-ultrasonic motor, it wouldn't be the fastest at slewing from one focus setting to another, but that's exactly the reason we measure focus determination speed, which is primarily a function of the camera body, vs focus adjustment speed, which is primarily a function of the lens.

Pentax does great in autofocus mode, but gains barely anything from prefocusing or manual focus mode.

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Last edited by Eruditass; 04-05-2011 at 10:36 AM.

[Siegfried]

Pentax does great in autofocus mode, but gains barely anything from prefocusing or manual focus mode.

Eruditass,
if you have a close look at the diagrams above you'll see that it gains 25% when going to MF from AF mode.

Mechanically K-5 isn't any slower then D90 so I hope (and gonna update that 'f/w wish-list' on the other thread) that they'll put it a new mode (say 'low-latency shooting mode') in a new f/w release - when those delays mentioned above in my screenshots are decreased probably with payoff in decreased quietness.

Zig

[Eruditass]

Doesn't seem match IR's numbers:

Pentax K-5 Digital Camera Performance - Initial Test - The Imaging Resource!

Perhaps it was a firmware update and that gives hope?

[Siegfried]

Eruditass,
There isn't a single standard in a shutter lag measurements or at least I'm not aware of it. I posted all the gathered details with so anybody having a ruler can do his own measurements according to any methodology desired: button to shutter, button to mirror up, etc. You can refer to the screenshots posted and measure it on your own.

I/R folks do not post such data so I have nothing to comment on their results. Moreover, I feel like I'm a bit biassed against their measurements and methodology since they add AF time into measured results and call it '... Shutter Lag Time' (where '...' can be Full Autofocus Single Area, Full Autofocus Auto Area and so forth). As mentioned earlier in this thread (I wonder if anybody reads the 1st pages before going with a quick reply) a shutter lag should not be confused with shot-taking-lag - the latter consists of a focus lag, a flash discharge lag (in a case of one is used), a shutter lag, etc. And btw there's also a photographer lag that can exceed all the other lags combined.

Zig

[Eruditass]

I believe my understanding of your test is correct, but your understanding of IR's test is not. Please correct me if I'm wrong.

If you read their description, they don't add actual focus time. The lens is already in focus. It's the time for the body to realize it is in focus:

To minimize the effect of different lens' focusing speed, we test AF-active shutter lag with the lens already set to the correct focal distance. Being an older design with a non-ultrasonic motor, it wouldn't be the fastest at slewing from one focus setting to another, but that's exactly the reason we measure focus determination speed, which is primarily a function of the camera body, vs focus adjustment speed, which is primarily a function of the lens.

They are all shot taking lag with slightly different situations.

Regardless, the relationship between prefocus lag or AF mode and MF should be consistent between the tests. That leads me to believe firmware changed something, as we're not looking at absolute time differences.

[Siegfried]

Eruditass,
I'm not a native English speaker or reader nor I have enough patience to read everything I read in detail - yep, I missed that. I'm wrong, sorry

But nevertheless until they post their screenshots (or better wav files) I can not comment the results they got.

Thanks,
Zig