D300 File Sizes

[Fips]

Hi everyone,

since I'm going to take pictures at a ski race at the weekend I thought it might be a good idea to do a quick estimate on how many batteries and memory cards I'll need. In the process I realized that the number of remaining pictures displayed by my D300 is way off from what I calculated. To be more precise it's only about 60% of what it should be based on the average file sizes. It's the same story for JPG, 12 bit raw, and 14 bit raw. For example my average file size for a 12 bit raw file with lossless compression is 12.5 MB (DPreview say 11.1 MB in their review) which would equate to 1,311 pictures on a 16 GB card. The D300 shows 769 remaining frames for an empty card. Any ideas what's going on? 

Cheers,  Philipp

[langier]

Simply reality vs. theory.

The counters on all my Nikon DSLRs are always conservative, which is good. I think that Nikon has programmed a fixed-size image for the exposures remaining estimate since each frame is slightly different when compressed and saved. My files seem to average 9.5-10 MB/file.

I shoot raw only and always get more frames per card than the counter shows. A rule of thumb for me is that 4-Gig card is about the equivalent of 10 rolls of 35mm film, 36 exposures. When I shot 4 GB cards, I usually got about 360 raw compressed images on any of my cameras. Today, shooting a 16 GB card is roughly 40 rolls equivalent--about 1400 images+.

As for batteries, using freshly-charged batteries, I'm getting probably 1000-1200 images per charge, if not more. In cold, this will be lower.

A good upgrade is to use the MBD-10 grip and both the battery in the camera for back-up and an EN-EL4a in the grip. You would then get better than 3,000 image per pair with power to spare and an extra frame per second rate with the camera on continuous.

[jonathanlung]

+1 on the conservative counter. The only time I've noticed this to be problematic is when using a nearly-full card and shooting a burst; the card will lock up and refuse to write if the camera doesn't think the card will have enough space (using the conservative calculations). The free-space indicator will hit zero and then slowly creep back up as the buffer empties and the images actually get written to the card.

In about -10ºC weather, I ought to get about 3500-4000 shots (based on the % drop for several hundred frames) with minimal chimping (taking a one or two second exposure check every twenty frames or so), no on-camera flash using AI-s lenses from my four-year old battery.
In warmer weather, using AF tends to double the rate at which my battery is drained and VR (I've only owned one VR lens and stopped using it years ago) doubles _that_. So VR + AF with no on-camera flash and minimal chimping might give you roughly 800 shots.

[Fips]

Thanks for the replies. I guess a conservative estimate in general is a good thing as you say, but being a whopping 40% off seems rather unnecessary 
Especially in the case of uncompressed raw files, which should always be the same size. Or am I missing something here?

Concerning batteries: How come you get get more shots in cold weather? It is my understanding that the internal impedance increases with decreasing temperature and thus the effective capacity should be lower.

[jonathanlung]

I don't get more shots in cold weather; I normally shoot with AI-s lenses and get ~4500-5000 shots (estimated -- I usually forget to recharge my battery unless I have a shoot coming up until it reads 25% remaining, which occurs after about 3500 shots) when it's warm.

Also, my compressed 12-bit NEF shots tend to weigh in at around 14MB on average, so maybe it's just as well that the camera is a bit more conservative