I guess this refers mostly to living things that move…
I usually can’t be bothered wading through heaps of photos looking for the ‘best’ shots, also I like macro and the flash tends to limit rapid-fire shooting… My time out observing is usually a bit limited too so my approach is:
Something marginally interesting - 1-2 shots, hope for the best
Something interesting - 3-5 shots, generally end up with at least one usable photo
My favourite taxons or something really unique - from 3 to 20 shots. I try to get best angles for ID, but it can be difficult when the subjects are fast moving. I’ve definitely missed a lot trying to focus well instead of pray and spray and pick through them later!
The way I see it, only one is necessary if you can catch it in a good pose. If the organism moves or if I get a different view on it, I might add another photo. With certain organisms though, especially crayfish or plants in my experience, it’s pretty much necessary to grab as many photos and angles as you can, because IDs can only be made with the most minute distinctions.
As @nickcarlson says, it depends on the organism. If I know I have a good shot, I’ll only take one, but discerning between a Downy and Hairy woodpeckers, beak size is needed, so two or three if they cooperate. I know dragonflies should have specific shots for best ID, but they rarely sit still long enough to compose shots. Same with butterflies - dorsal surface is best, but if it won’t open it’s wings, ventral will have to do. Posting is a different matter - I pick the best and put up one or two. I’ve seen up to six posted of the same moth, most of which add nothing to the ID.
You have to know what you’re shooting. Each type of organism has different details that are needed for photo identification. If you’re shooting a tree with leaves maybe just one photo is enough. A bird may need one photo. Even a moss may need one photo, if it’s the right moss and the right photo. Other organisms may need multiple photos and perhaps even photos through a microscope to show alar cells or reproductive structures. So your question can’t be answered until you describe what organisms you are shooting. And then, you might be able to answer it yourself once you consider what you are shooting and look up the necessary details that you need to show for that type of organism. As for dealing with movement, you need to consider what behaviors will slow your organism down so you can get the shots you need.
I’m probably guilty of “multiple pictures of the same organism which add nothing to the ID”, but that’s because for a lot of taxa, I don’t know what the important bits are - especially characters of leaf pubescence in plants. Too many times I’ve taken a picture in the field, narrowed it down to 2 or three species, and then just needed to answer a simple question of pubescence on the abaxial leaf surface, and not had pictures for it. I err on the side of “too much info” because as I’m not an expert in these taxa, I don’t know what the minimum characters are for sufficient ID.
Did not mean to castigate you! Just, for moths, the dorsal surface is mainly sufficient. Or the male ‘junk’ (for some species). Other taxa, I don’t know what is necessary, so I’d probably do the same as you.
A minor point on the butterflies here. As someone who identifies a lot of butterflies, there may be more that can be best identified by a good view of the ventral hindwing than the dorsal side. Blues are the worst for dorsal views. The large majority of Polyommatini - Blues I know have an upper surface that is all blue with no markings, with all of the markings on the ventral side, and the hindwing is the only one that is fully exposed, and which the guides best show the field marks for.
As someone who does more identifying than observing, identifying a wide range of taxa, I would say that you want to answer the question: Might this additional photo show different distinguishing features, or might it show the same features better than the last photo? Some might show features on the upper side better, some might show features on the underside better, and some might show features on the side better. Then there will be individual features, seen from each side, that can be seen better in one view / photo than another. Some could give a closer view than another. If an additional photo shows a feature better, or gives a close view better, or a broader view better, I would use the photo, if a photo doesn’t show anything better than another photo, I wouldn’t use it. It isn’t the number of additional photos that is so important, but the number of features shown by your set of photos that is more important.
I do actually know that (theoretically) - unfortunately, I’m not versatile when it comes to butterflies. They confuse me! So I want to get a dorsal shot shot so I at least can take a stab at it! Thanks for the communication, though. I did not know that about Blues.
Happy to add my perspective here. Thinking further, a preference for dorsal or ventral on butterflies depends on each group. Any species is likely to be recognized to be a member of a group by a wider audience from a dorsal view. That said, a wider audience is likely to recognize a Blue as a Blue from the dorsal side, while those who know the Blues are more likely to know the species from the ventral side. The same is true for some other butterfly groups.
If it’s an interesting bee (a species new to me, or one that I’ve observed before but without enough detail to ID to species) I’ll frequently take dozens of shots in the hope that some will show new features and will be in decent focus. I’ll try to cycle through face, head and scutum, wings, rear, and legs (unless I know there’s one character that is critical, and concentrate there). Back home it takes a while to sort through the blurry pictures, and the beautiful pictures of flowers that the bee has just left, to find any decent ones. In the end it is rare that more than 4 add independent value to the observation.
As others said, depends on taxa and circumstances, plus amount of shots doesn’t equal amount of uploaded pictures, to get an observation with one good pic you may need to get 20 of the same angle just to get all the needed details in focus as each mm counts in this process. I know there’re harder plant taxa, like Alchemilla, so I photograph each possible part of the plant that is not in the ground, it often means there’ll be duplicates, but you can choose the best one when uploading, and still it’ll be around 10 or more just because there’re too many parts that you need to photograph. And of course hard insect mean about 20 pics just because it’s a hard group where you can’t show only a few details and need all of them.
oh no, I’m guilty of this. I upload multiple pictures because I struggle with a proper light/flash system that prevents light reflection off the scales, so I provide several dorsal shots with different parts of the wings not reflecting light to show the scale patterns. I also don’t know the species in my region, so I also err on getting more information/pictures than needed. I think as an identifier, it’s more frustrating to have a lack of angles than redundancies, but that’s my own limited experience
The real question is how many shots do you need to take to get 1 or 2 that are in focus and diagnostic for the species? That depends a lot on one’s skill as a photographer, the equipment you’re using, and if the organism is cooperative. I can’t always tell if my photos are particularly sharp, whether I use my camera or my phone, so I take a lot of duplicates with different settings or angles and hope at least one is really sharp. If the animal is moving or the wind is blowing the plant I might take a dozen pictures of one subject. Sometimes more if it’s really interesting to me. With digital, it’s no big concern. I could never do that in the old days with a film camera.
For an organism I know, one photo may be enough, if it shows the parts I know identifiers will need in order to confirm the ID. For a plant I don’t know, probably 5 photos needed (front and side of flower, top and bottom of leaves, whole plant). And then there’s the focus issue! So more photos. For insects, which I don’t know well, lots of photos until I’m tired of taking them or the insect leaves, because the parts will be out of focus or moving. I try to limit the number of photos I actually post to a diversity of views, but I have to admit that sometimes I post too many of one angle, especially if the darn bug didn’t move until, zip, it was gone.
I understand that people don’t want to post redundant pictures that add nothing to the ID, but as someone who is working on a pattern recognition project to identify individual snakes it is really helpful when more than one picture is posted. The program needs multiple pictures of each individual in order to analyze them, and very often people only post one photo. The way I see it, you never know what projects ecologists are using these photos for so if you have more than one pic I say post them!
I am good at identifying 2 species and can usually tell from the first picture. It does not bother me if there are more, and one of the species I identify sometimes has the key info in another picture. If I was a real botanist, I probably wouldn’t need the other pictures for these species, since there are multiple ways to identify easy species like mine, but I’m not a botanist and I am happy for the help when I need it.