Taking a trip with your D7 and worried about storage? Here is what do do.
Obviously, you will have limited storage on your trip. Maybe you are just taking flash cards, or maybe you have a laptop or device to offload your shots, but unless you have considerable storage you will have to put yourself on a picture budget.
So, why can't you just divide some numbers , the size of your shots into your storage and get a result? Unfortunately, it is more complicated than that for two reasons.
1) The size of each actual shot will vary. The actual size will depend on what you take a picture of, and how much JPEG can compress it. A picture of a white wall will be much smaller than a complex picture such as a close up of sand on a beach. That is why Minolta can't give you an exact number for how many shots will fit on a card.
2) There is a two way trade off for picture quality. The resolution and compresson level both factor in. Generally, it is better to use higher resolution and higher compression than lower resolution and lower compression.
Overview: The first thing to do in planning for your trip is to figure out how many shots that you need want to take on your trip per day. Next add up all of your storage that you can muster. That is what you have to work with. Then you will invent a picture budget (below) and will divide these these shots into two types or maybe three groups, casual (pictures of people on your bus) and important (once in a lifetime shots of the Parthenon or Loch Ness Monster), and possibliy a third "throw away" class. You will probably want to take a lot more casual shots than important shots.
Next, you have to decide what camera resolution (2560, 1600 or 1280) and what compression (Fine, Standard, Economy) you will want to use for the two types of shots (casual and important). Then I recommend storing the resolution and quality for the two groups of shots in 2 or all 3 of the camera memories for easy recall later.
Here are the approximate sizes that the vs. combinations produce in real life. Note that the actual size varies with how compressible the scene is, so that these are averages, but taken from some of my actual trips.
2560 Fine - 2000K
2560 Standard - 1000K
2560 Economy - 600K
1600 Fine - 900K
1600 Standard - 450K
1600 Economy - 300K
1280 Fine - 500K
1280 Standard - 300K
1280 Economy - 200K
Now before deciding note a few things.
* First, it is hard to actually see the difference between Standard and Fine on any of the modes. You might want to use Fine only for those very important shots.
* Second, it always looks better to use higher resolution than lower resolution and less compression. Take some test shots and see for yourself, don't take my word for it.
* Third, and this is important, note that you don't really save anything by using Fine at a lower resolution vs. Standard at a higher resolution, and the shot at Standard at higher resolution will look far better. For example, 2560 at Standard produces about a 1000K file, and 1600 at fine produces a 900K file. You aren't saving much if anything and the 2560 Standard shots will look a LOT better than the 1600 Fine shots because of the higher resolution. Stay away from these space eating combinations that don't look as good as better combinations.
It makes no sense to use the following combinations...
* 1600 Fine - Use 2560 Standard instead
* 1280 Fine - Use 1600 instead or even 2560 Economy! Even at Economy setting, the a shot at 2560 pixels will look far better than using only 1280 pixels.
As for Standard compression at lower resolution vs. Economy at higher, It all depends on how you feel about the Economy setting at 2560. Yes, you can see some JPEG artifacts if you look closely, but I feel that the increased resolution outweighs this disadvantage. You can always resample later to lower resolution and the artifacts will go away. You might want to try some test shots yourself.
I'd work with the following three combinations, programmed into the memories.
Memory 1 - 2560 Fine - 2000KB - Use for most important shots.
Memory 2 - 2560 Standard - 1000KB Use for everyday shots.
(Optional for low space) 2560 Economy - 600KB or 1600 Standard - 450KB (your choice, take some test shots) - Only use for your everyday shots if you are running over budget during your trip and are low on space
Memory 3 - 1600 Standard - 450KB use for "throw away" shots. These will print perfect 4x6 and 5x7, and you could even coax an 8x10 out of these if you wanted to.
(Optional for low space) 1600 Economy - 300KB Only use if you are REALLY desperate for space.
Needless to say, the movie feature just eats space, you can't really use it at all on a trip with limited space. So does the UHS mode, if you must use it set Standard compression and delete any extra shots later.
So, working with the three sizes above, I'd work out my budget.
20 important shots per day @ 2MB = 40MB
60 everyday shots @ 1MB = 60MB
60 throw away shots. @ 0.45MB = 27MB
For 127 MB per day. A 6 day trip would fit on a 521 and a 256MB card. Or, you can work backwards from your existing card sizes and figure out what your budget will be.
Obviously, if you are running under budget, you can loosen up a little. You probably will not really take 140 shots per day as above, and most of the time I find myself running way under budget.
If you are running over budget...
1) Delete some shots you hate, especially Fine mode shots.
2) Switch to lower modes. You will most likely be perfectly happy with using Standard (memory 2) instead of Fine (memory 1)
3) Switch to one of the emergency modes.
4) Buy a bigger card next time. ha.