Digital Camera Question

[BOBOT]

This weekend while taking lots of shots in varying lighting conditions (in a museum) I noticed that was taking a LOT of time - up to 5-6 seconds - to write to the SD card before I could take another shot. I had not had (or noticed) the problem before.

Back home I did some experimenting. Thinking it might have something to do with the size of the SD card - 2 Gig - I changed back to the 1 Gig I had used previously, but same thing. Then I noticed that the problem seemed to only happen with shots taken in relatively low light requiring open aperature/slow shutter & flash; in outdoor ambient light it is ready to go nearly instantly.

Camera is a Canon Powershot A540; SD cards are SanDisc & Kingston.

Any ideas?

 

[Rockisle]

Bobot, charge or change the battery. The flash uses a lot of power.

 

[My Dream]

?, Welcome, it took you almost 2 years to post that. I hope to see you posting more often.

 

[cute fuzzy bunny]

It could be photo processing time. Cameras have a photo processing chip in them that makes adjustments and compresses the photo before storage. Perhaps dim pictures take longer to process on your particular camera model. Check some of the photo review web sites which include this stat in their reviews to see if your model takes more or less time between shots to process photos.

Its also possible that your camera, for whatever reason, decided that the flash chip you inserted is a lower speed than what it actually is. Remove the flash chip and the battery from the camera, wait a minute or so and put them both back in, battery first. See if it changes the store speed.

 

[TromboneAl]

I agree with CFB, camera is doing extra processing for the low light image. Here's what it's thinking:

"Oh, Geez, he took another one of those low light pictures again. Now I have to fix it up for him. Work work work. Averaging, counting, summing. I wish he'd go outside again."

 

[cute fuzzy bunny]

Theres another plausible flip side explanation...if you've somehow set the camera to store images in a 'raw' or uncompressed format instead of the usual jpeg compression setting, that can result in images as much as 10-40x as much data being written to the flash chip. Check your settings for a 'normal/fine/superfine' setting that you might have inadvertently changed or a 'raw image' or 'no compression' option.

Its also possible that there is some camera smarts being employed...when in auto mode and shooting at high ISO levels, the camera may switch to a raw mode to improve the shot quality.

 

[mathjak107]

the camera may be trying to apply low light noise reduction. i just got a nikon d80 and have spent the last month cramming and learning. there is so much to learn. not only about photography but now the digital processing end as im starting to shoot raw

 

[Goonie]

I noticed that as my SD card got more pix on it (lots more), that the time to process before the next pic could be shot lengthened greatly. I slapped in a new empty SD card, and the the time between shots went back down to normal. I switched back to the first SD card, and the process time increased greatly again.

(I'm using a Kodak Easyshare with 1 & 2 gig SD's)

 

[renegade]

Two things are likely at play here. Digital images in low light have a very high noise ratio, and noise is data. If saving as JPG files, then the camera is also applying all of it's noise reduction powers as it processes the image, resulting in longer times to process and write. Since noise is data, the image files are also larger, taking longer to write to the card.
Try this experiment:
With an empty memory card, take one shot outdoors in good light, and one indoors in poor light.
download the files to the computer and look at file size. The low-light image is likely 1/3 to 1/2 larger in size than the well-lit (low noise) image.

 

[ERD50]

I noticed that as my SD card got more pix on it (lots more), that the time to process before the next pic could be shot lengthened greatly. I slapped in a new empty SD card, and the the time between shots went back down to normal. I switched back to the first SD card, and the process time increased greatly again.

(I'm using a Kodak Easyshare with 1 & 2 gig SD's)

You could also try re-formatting the card. I understand the pros do that often.

Considering you saw the problem with two diff cards, the other ideas raised may be more to the point, but it couldn't hurt.

I'd bet on the low light processing ideas, or that you did set the camera to a higher size format.

-ERD50

 

[Goonie]

You could also try re-formatting the card. I understand the pros do that often.

Considering you saw the problem with two diff cards, the other ideas raised may be more to the point, but it couldn't hurt.

I'd bet on the low light processing ideas, or that you did set the camera to a higher size format.

-ERD50

In my case, both cards were fairly quick when empty. Both cards were fairly (quite) slow when more full. I didn't notice any considerable difference in speed due to lighting or lack thereof.

I'll see how things go when I switch cameras and card-types some time soon.

 

[BOBOT]

All good insightful info, thanks. I think all of the comments relating to image processing for low light/noise, as well as pix size & density are right on. I obviously have a lot of 'sperimenting to do -- & now I have the time to do it!

 

[cute fuzzy bunny]

I see that your camera has the same digic ii processor that my camera does.

According to the documentation, the noise reduction circuitry kicks in automatically on low light shots and drops the compression ratio.