ISO changes automatically on my Nikon D5100 ??!!

[Derrel]

I think that 800 ISO and 1/800 second, for most uses, is not a good combination. First off, ISO 800 is "not that high" an ISO level, at least in daylight hours. But more pressing is the shutter speed minimum of 1/800 second; that is a very fast minimum speed. It would be appropriate if you're shooting a lot say, one-handed in a saltwater fishing boat, where there is a ton of bright reflected light, and you could get exposures of say f/16 at ISO 400 at 1/800 second. But the minimum floor of 1/800 second is a very fast speed, especially for shorter lenses, and will cause the ISO to be driven UP much of the time. I think you need a lower minimum speed: say 1/160 second for an 18-55 zoom, and with a longer lens, say 1/320 second minimum, perhaps 1/400 or 1/500. As to the maximum ISO, I'd say maybe set that to allow it to go up to ISO 1,600 or ISO 2,000 or so--just in case it's needed. It's unlikely to go to such a high ISO as 1,600 or 2,000, because you've got a more-sensible minimum shutter speed enabled.

Thank you Derrell for explaining that I appreciate it. I am mostly shooting backyard birds in flight and trying to get detailed wing shots. Would you say the settings you mentioned would work for that using the 55-300 lens? Of course when I am out and about I shoot landscapes and whatever catches my eye.

Well, if your goal is fast shutter speeds and motion-stopping of bird wings, then a 1/800 second minimum speed makes sense, but for "generalist" use, the settings are biased too much in favor of shutter speed. The reason the user gets to choose the preferred ISO, and the minimum guaranteed shutter speed, and the Maximum ISO is so that the user can pre-determine what the best parameters are, for their use. My question would be: why are you in Aperture-priority mode and not Shutter priority? Or, are you always shooting wide-open, in order to get the fastest shutter speed you can get?

 

[annamaria]

Well, if your goal is fast shutter speeds and motion-stopping of bird wings, then a 1/800 second minimum speed makes sense, but for "generalist" use, the settings are biased too much in favor of shutter speed. The reason the user gets to choose the preferred ISO, and the minimum guaranteed shutter speed, and the Maximum ISO is so that the user can pre-determine what the best parameters are, for their use. My question would be: why are you in Aperture-priority mode and not Shutter priority? Or, are you always shooting wide-open, in order to get the fastest shutter speed you can get?

Well from what I have heard lots of photographers use aperture priority, and from what i have read online etc. I have tried using shutter priority but the photos come out awful, not sure what I am doing wrong. Still learning the ropes. So to be on the safe side I use aperture priority.

 

[annamaria]

Well from what I have heard lots of photographers use aperture priority, and from what i have read online etc. I have tried using shutter priority but the photos come out awful, not sure what I am doing wrong. Still learning the ropes. So to be on the safe side I use aperture priority. Forgot to mention I usually have it on f5.6.

 

[Derrel]

So, yeah, with that lens at its longer end, f/5.6 is "wide-open"; setting the minimum shutter speed to 1/800 second ensures that there will be a fast enough shutter speed to hopefully stop most of the wing movement of the birds.

 

[SCraig]

Well from what I have heard lots of photographers use aperture priority, and from what i have read online etc. I have tried using shutter priority but the photos come out awful, not sure what I am doing wrong. Still learning the ropes. So to be on the safe side I use aperture priority. Forgot to mention I usually have it on f5.6.

Quick recommendation (as opposed to rule) of thumb: If the subject is moving use shutter priority, if the subject is still use aperture priority. On moving subjects this ensures that the meter doesn't do something stupid to your shutter speed, and on still subjects it insures that the metering system doesn't do something stupid to your depth of field. As with all recommendations and rules, there are always exceptions.

 

[annamaria]

So, yeah, with that lens at its longer end, f/5.6 is "wide-open"; setting the minimum shutter speed to 1/800 second ensures that there will be a fast enough shutter speed to hopefully stop most of the wing movement of the birds.

Thanks again Derrell and hopefully yes

 

[annamaria]

Quick recommendation (as opposed to rule) of thumb: If the subject is moving use shutter priority, if the subject is still use aperture priority. On moving subjects this ensures that the meter doesn't do something stupid to your shutter speed, and on still subjects it insures that the metering system doesn't do something stupid to your depth of field. As with all recommendations and rules, there are always exceptions.

I will try to remember that and try it out. I am not that good with shutter priority yet, need lots of practice. Thanks for explaining it.