confused newbie - raw read times

[rosscopeeko]

hello there.
Look this might sound stupid but i'm looking at trading all my film gear in to get a D10 - however I have read that if you save your pics in raw format it can take up to 40 seconds to save to the card. During this time can you take more pics (does the camera have a buffer) or do you have to twiddle your thumbs while waiting for the camera to save the image??

Yours confused

Rossco

[robertwgross]

rosscopeeko wrote:
hello there.
Look this might sound stupid but i'm looking at trading all my film gear in to get a D10 - however I have read that if you save your pics in raw format it can take up to 40 seconds to save to the card. During this time can you take more pics (does the camera have a buffer) or do you have to twiddle your thumbs while waiting for the camera to save the image??

Yours confused

Rossco

First of all, D10 is a Nikon designation.

Possibly you meant a Canon 10D. Let me parse out your question. I think you are selecting raw format for the images. If you shoot one frame, then it will take several seconds to completely store that data off to the CF memory. In the mean time, the data is only in the buffer and maybe shown on the rear display. If you fire off several shots in a hurry, then the camera will take several times several seconds to completely store all of that data off to the CF memory. As long as the buffer is full, you can't shoot anything else. However, if the buffer is not full, like if you just shot one, then the camera gives priority to taking another fresh shot... until the buffer fills again. It works the same way for JPEG also, but JPEG files tend to be much smaller, so the whole mechanism works quicker.

---Bob Gross---

[rosscopeeko]

Hi, thanks for that. Sorry I meant 10D. I currently take wedding pics, so I need high def (hence raw), but I can't wait around. I don't mind waiting for the camera to transfer images to disk as long as I can continue to take pics - do you know how big the "buffer" is? I know a high res raw pic can get up to 15mb in size.

Regards,

Rossco

[robertwgross]

I have the Canon D60, which is the older brother of the 10D. So, it is almost the same, but slightly slower. Further, I use only standard CF cards, nothing fast.

On mine, it takes about six seconds for each frame to cycle through the buffer. So, if I fired off eight in a row (the max on the D60), I would have to wait roughly 48 seconds for the buffer to be clear. However, when _I_ shoot weddings, all of the indoor work uses a Canon 550EX flash with standard batteries. As a result, I have to wait for the 550EX to recycle instead of waiting for the camera.

The very first month I had the camera, I was up in snow country, cross-country skiing along with the camera inside my coat. All of a sudden, I heard something coming up behind me on the trail. I whipped out the camera as I stopped to look back, and there was a dog sled racing toward me. I took one step to the side, and then fired off one shot, two shots, three shots.... until the entire eight shot buffer was full. Then the dog sled was past me. Luckily, the camera was in Sports mode, so each and every frame was perfect without blur. It works for me.

---Bob Gross---

[rosscopeeko]

Bob, thanks for that. Since you mentioned the speedlite - what is the refresh rate on a fresh set of batteries? That was another one of my questions that I haven't gotten round to ask,

Cheers,

Rossco

[robertwgross]

Also, I think you meant to say "write times". Your camera buffer is writing the file to the CF card. Later on, when you transfer the file from the CF card to the computer, then you are reading from the CF card (but that step does not depend on the camera's buffer).

---Bob Gross---

[reittila]

robertwgross wrote:
I have the Canon D60, which is the older brother of the 10D. So, it is almost the same, but slightly slower. ..

Actually D60's writing speed is faster than 10D's
Check for D60 (http://216.197.110.125/bins/multi_page.asp?cid=6007-6012) and 10D (http://216.197.110.125/bins/multi_page.asp?cid=6007-6111)

[robertwgross]

rosscopeeko wrote:
Bob, thanks for that. Since you mentioned the speedlite - what is the refresh rate on a fresh set of batteries?

Uhhh. I can't place my hands on my 550EX manual right now, but I have my 420EX manual. It uses four AA alkaline batteries. Recycling time approx. 0.1-7.5 seconds.

You might ask the next question. Why is there such a range of time?

If the flash is commanded to *blast* the light out there, then it draws the full charge off the capacitor, and then the capacitor must be recharged, so maybe 7.5 seconds. If the flash is commanded to cut down its light intensity (like for a closeup), then only a fraction of the main capacitor charge is dumped, so it can then recharge that in a second or less.

---Bob Gross---

[Dave I]

You've got your stats mixed up. The 40 seconds quote you read was probably for the full buffer.

According to DPReview's timings, it takes about 5-6 seconds to write out a RAW file, and can take up to 55 seconds to write a full buffer of 9 RAWs. However, if you shoot the full 9 shots, it's only a 1.9 sec wait until you can shoot one more, or 25 sec till you can shoot another 8 shot burst (it compresses the last burst as it's writing).

If you don't actually shoot a full 3.3fps burst of 9 shots, it can be quite difficult to actually fill the buffer.

Also, a max size RAW file would be about 6MB, not 15.

[Webster]

If you don't actually shoot a full 3.3fps burst of 9 shots, it can be quite difficult to actually fill the buffer.


If the 10D is like the D60, it's actually pretty easy to fill up the buffer. Since it doesn't write to the CF card while the shutter is half pressed, all you have to do is shoot, focus (half-press) shoot, focus, etc. Then wonder why it won't focus again. And if you've got a real learning disability, you still do that occasionally even after using the camera all year.