700D - 45MB/s for long exposure and RAW?

Mache

Mache

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Sean
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Hi All, :)

I'm getting a 'Busy... Please Wait' on RAW shots over 25sec exposures and was wondering whether I would need a faster memory card...

I currently have a SanDisk 16gb 45MB/s, which i've read isn't fast enough for my camera. Before I had the 1100D with same settings and i didn't receive any 'busy... please wait' messages. Its kinda a pain as setting up with a Giga Pro T isn't working out as i have to wait a 15sec delay between each shot.

Could someone shed some light on why this is happening and point me in the right direction of a new card?

Thanks
 
Switch off long exposure noise reduction. It takes a second exposure of the same length with the shutter closed, then maps the hot pixels to remove them in camera. That's what the "busy" message is saying.. that it's taking a second exposure of the same length, then processing the two images.

It's nothing to do with the card.
 
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I'd guess what you're waiting for is the camera processing the file rather than the writing of the file to the card as it takes time to apply noise reduction etc. 45MB/s is a fast enough card for a single ~20MB raw file.

I seldom do long exposures, so others might explain why I'm wrong.
 
Mache said:
Hi All, :)

I'm getting a 'Busy... Please Wait' on RAW shots over 25sec exposures and was wondering whether I would need a faster memory card...

I currently have a SanDisk 16gb 45MB/s, which i've read isn't fast enough for my camera. Before I had the 1100D with same settings and i didn't receive any 'busy... please wait' messages. Its kinda a pain as setting up with a Giga Pro T isn't working out as i have to wait a 15sec delay between each shot.

Could someone shed some light on why this is happening and point me in the right direction of a new card?

Thanks
Click to expand...
Where have you read that a class 10 card isn't fast enough? Class 6 or above

You have also gone form 12 to 18MP but if you switch off noise reduction you'll find that's your issue
 
Too slow eh- that's multi-tasking for you:D
 
Switch off LONG EXPOSURE noise reduction... not the normal high ISO NR.. the latter will not be applied in RAW anyway, but long exposure NR is. Switch off long exposure NR.
 
Ahh well that's clever, thanks a lot guys!

Just another question though if i may, i like to do a lot of astrophotography... (when the sky's clear!) do you think the noise reduction would help me out?
 
Not really. Unless your exposures are very long, there won't be many hot pixels (usually seen as red, or green or blue single pixels against the dark background) and what there is are easily removed manually.

If you're taking star trails for example, you can't use long exposure NR as the gap between exposures will show when you stack them, so always turn it off for stacked star trails.

For single images you can leave it on if you want... it just takes twice as long take the shot is all, but it will remove any hot pixels. Depends how your camera performs. I find my D800E is quite bad for hot pixels once past a couple of minutes, yet my D610 is not.

Suck it and see as they say :)

Long exposure NR is not "noise reduction" as in reducing noise/grain... it's purely to remove hot pixels. As for normal high ISO NR... it doesn't work in RAW anyway, so you can apply that in lightroom or Adobe ACR later.
 
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Thanks David.

I usually take quite a few and stack using Deep Sky Stacker which detects hot pixels and removes with required shots with the same exposure, temperature etc

Thanks again,

Sean
 
If you're stacking... definitely do NOT use long exposure NR :)

As you say, most stacking software can load a "dark" file and use it to map hot pixels, so you can take your set of images to stack without any long exposure NR, then when finished, just manually take an exposure of the same length with the lens cap on, and use this as your dark reference file. It's important you do this at the same temperature, as this effects hot pixels. You'll have more hot pixels on a hot summer night that you would at -10C in winter. So always take a "dark" exposure at the end of each astro session if you want to map hot pixels. (BTW.. that's not why they're called hot pixels :))
 
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Believe it or not but i have a Darks folder for every season of the year! :) Though i do have different lenses now so i may have to change that. :(
 
Mache said:
Believe it or not but i have a Darks folder for every season of the year! :) Though i do have different lenses now so i may have to change that. :(
Click to expand...

Lenses used will not affect darks, as they are dark :) You generate them with the lens cap on. You don't even need a lens attached to take a dark... just the body cap :)

If you are used to taking darks, then you definitely do not need long exposure NR on... so switch it off. Darks are sensitive to temperature though, so it's still wise to generate a dark for each session. No need to archive them... just take one per session so you can be sure it's generated under the same temperature conditions.
 
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Thanks David Shall try it out again when the clouds clear!

Cheers
 
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