hi what is the best size sd card if i am going to leave my cam trap out for a week
8 GB, 16GB, 32GB are the best ones.
I use 8GB. I think that give over 2 hours on the HD video setting. I guess it depends how busy your site is.
8GB is more than enough. I leave my Acorn out for a week shooting 60s videos and there's always plenty of space left on a 4GB card on an active badger sett with lots of other wildlife during the daytime.
What camera trap are you using?
I have been using camera traps for years especially the Bushnell and Stealth cam ranges whic are the two leading brands and was one of the first to import them so I have used alot of the range in many different situations and I have learnt alot of factors can come into play from activity in the area to settings on the camera trap ie.quality(HD, AVI), sound and recording time so to be safe and avoid missing any extra activity I would go for the middle option which is a 16GB sd card.
Which do you use photo mode or video mode?
Then 4GB should be fine, if you start using video then I would use a 8GB/16GB.
Unless you're using an external power supply, your batteries will be dead long before you fill a 16B card, even shooting one minute HD videos. The only exception to this is likely to be if the location has constant wildlife activity. Anywhere where the activity is intermittent such as wildlife trails or badger setts will require a much smaller capacity card. I usually retrieve my Acorn cards at least once a week, and often have up to 80 one minute HD videos, and I only use 4GB cards,even though I have 8GB cards available. I would advise trying it for a week with a 4GB card and see how many images you get and how much power, if any, is left in your batteries. Arguably, a more pertinent question would be: 'Which batteries are best to use in a trail cam?'. ;)
I use a 16Gb card and have had no trouble with my batteries(lithnium) used since before Xmas but not all the time.In the last weeks since my Hedgehogs have come back I have recorded one minute long clips at night with a delay of just 45 secs.I down load images on the card every morning. downloaded at least 100. With the 16GB leaving out for a week you should not have trouble with high quality Lithnium batteries your delay needs to be several minutes perhaps 30. You will get many clips but thats part of the fun of these cameras.