asjohnston3 Loc: Irving, TX

Pretty much all of my general photography is in aperture priority mode. I'm currently trying out the auto-ISO feature on my new D7100. It allows faster shutter speeds but that's because it it almost always routinely picks an ISO quite a bit higher than I would normally use. Before I limited it to a max of 1600 it would bump it up to 3200 for some shots..... I know the current crop of DSLR's are capable of functioning at pretty high ISO's but how high is too high?..... Keep in mind that I'd like to be able to print at 11x14 or preferably 20x26 without noticeable artifacts as a general rule.

rjaywallace Loc: Wisconsin

Bert, I think you've pretty well answered your own question, not that that's a bad thing. At what point - ISO-wise - are you likely to start seeing artifacts when you print large images shot with your camera(s)? Then try not to go to or beyond that ISO level. If that is 3200 or 5000 or 6400, that's where you should stop. I don't think there is a hard and fast rule for a given camera (altho DPReview would like to say there is) or for all photographers.

Apaflo Loc: Anchorage, Alaska

Which exposure mode to use depends greatly on what you are shooting. There are times when Aperture Priority is absolutely the best, others when Shutter Priority is better, and others when Manual Mode is best. I personally do not like mixing Auto-ISO with either of the three (A, S, and P) auto exposure modes, but I find it just wonderful for use with Manual mode.

I can't tell you which is best for your use, but given what you've indicated about printing sizes you should probably consider, when shooting with a D7100, ISO 2000 as a maximum for normal use. That will produce, if you nail the exposure, a dynamic range of 6.5 f/stops. Lower is "wasted", but higher than that and it is definitely going to show up as noise unless you get very comfortable with some complex post processing.

An ISO lower than 2000 will allow a little leeway on exposure that is easy to make use of with only a small effort in post processing, so it's a good thing. Otherwise, how you get any given ISO, whether manual or automatically, is not important. With Manual Mode exposure and Auto-ISO it is very easy to choose any of f/stop (manually), shutter speed (manually), or ISO (adjust Exposure Compensation). Changing exposure will cause an automatic adjustment in ISO. Keeping the same exposure and adjusting Exposure Compensation is going lighten/darken you image.

Another obvious comment is that, while I can't tell for sure without knowing what you shoot, for most things a FF camera would be better than the D7100 for printing large. There are specific cases where that is not true, and given the added cost it might not be a reasonable option. But the maximum ISO without problems jumps from ISO 2000 with a D7100 to ISO 4000 with a D610...

davidrb Loc: Half way there on the 45th Parallel

You have initiated a topic that will either die on the vine or go like hell. Every model DSLR has a sensor/processor relationship that is peculiar to that particular model. That same processor might work differently with a different sensor. Then you have to include different models and of course makes. Upon receiving my 1-Dx I played with it in most modes just to see what it was doing. The auto-ISO was amazing! 25,600 was not a number the camera feared. It seemed far more comfortable at that ISO than at lower numbers. Will my 5-D MkII work at that number? I do not think so. Auto-ISO is just a mode on the camera. How and whether it is used depends entirely upon the shooter. Each individual has her/his own preference. This is one of those "settings" that some people are always asking others for. If you have to ask you need to learn. It is not a flaw to not know.

Macronaut Loc: Redondo Beach,Ca.

Perhaps a little experimentation is in order. Set your camera up for various high ISOs with the appropriate shutter speeds and aperture settings, take some pictures, then get them onto your computer and judge what is acceptable noise to you. Or if removing any noise with the proper software is or isn't too detrimental to IQ.

I have recently done just that with a new camera and new lens. the noise was perfectly acceptable for some uses and not so much for others.

Of course my objective is to keep the ISO as low as possible but, there may be situations where high ISO is the only way to get the shot.

EDIT: I have not yet tried the auto ISO on my 810 or 7100.

blackest Loc: Ireland

There is an interesting couple of things known as native and extended iso

http://petapixel.com/2015/06/24/native-versus-extended-the-science-and-marketing-of-iso-ranges/ Its generally better to use a multiple of base iso than an inbetween number.

Apaflo Loc: Anchorage, Alaska

The cited article is flawed with technical errors. It would have been accurate prior to maybe 2008, but it does not take into account most of the better sensors on current camera models.

The use of "inbetween" ISO values does still apply to many Canon models, but not to any of the current Nikon models.

Check out one of Bill Claff's graphs to see what they are talking about. Note the graph for the Canon EOS 70D, which is included because it is about the worst example of all. This first chart also shows a Canon 7DMII which only shows the effect at ISO's below 800. And it shows the Canon 1DX, which is not a great sensor but doesn't have any of that particular effect. The Canon 5DSR is another model that is okay.

http://www.photonstophotos.net/Charts/PDR.htm#Canon%20EOS%201D%20X,Canon%20EOS%2070D,Canon%20EOS%207D%20Mark%20II

For comparison, here is a chart showing Nikon models. The older out of production D700 shows an effect similar to the current Canon 7DMII. All of the current Nikon models have graphs similar to that show for the D610 (including all of the APS-C sensor cameras). The Nikon Df, D4 and D4S sensors do all show one small wrinkle at below ISO 200 (at the actual "native" ISO of the sensor), but it is a fraction of an f/stop and insignificant.

http://www.photonstophotos.net/Charts/PDR.htm#Nikon%20D610,Nikon%20D700

But another point where the article is totally out of date is the difference in the way ISO's in the "native range", stated to use analog amplification, and those in "extended range" are processed.

Today analog amplification is used up to somewhere between 1200 and 2000. Everything above that is digitial (which they falsely say is software multiplication). It is absolutely not the same as pulling a file up in an editor and using an "exposure slider". The camera is using hardware "digital" multiplication in the Analog-Digital-Converter by changing the analog compare voltage to get different digital output values. It produces less quantization distortion than the software digital multiplication of an editor.

Hence, as opposed to what that article says, with all Nikon and at least some Canon cameras the "inbetween" values are perfectly acceptable. In fact even on the Canon sensors the effect probably is not significant at the low ISO values where it exists. And if a higher ISO is necessary, set that with the camera rather than adjusting exposure in post processing.

Rongnongno Loc: FL

You might want to read my post here...

Delderby Loc: Derby UK

Know your camera inside outside and back-to-front. I have often thought of updating my MFTs - and then decided that there is NO substitute for REALLY knowing the camera - and stuck with what I have. Better than a new learn curve! My max print size is A4 and I do my own printing. Usually auto ISO limited to 800 on my G5, 400 on my G2. Remember - bigger prints will have a different comfortable view distance. Avoid pixel peeping - it will drive you nuts. I believe ideal album size is 6x4 or 7x5. :-)

mikedidi46 Loc: WINTER SPRINGS, FLORIDA

I use Auto-ISO when I am in the city, as it allows for me to not waste or lose a shot.

Delderby Loc: Derby UK

Like your Avatar - have you got a full size to post? :-)

dsmeltz Loc: Philadelphia

I shoot a lot of marathons. I tend to use auto ISO with a limit up to about an hour or so after the start of a race. The light keeps changing and the shadows can get a little funky. I don't want to be thinking about ISO too much at that point. But once the sun is up a bit, I switch to setting ISO manually. I tend to shoot in manual mode as shutter speed must be maintained, and aperture really affects the changing compositional demands and has to be controlled.

JaiGieEse Loc: Foxworth, MS

Not long after I got my D7000 (for Christmas, right about two months before Nikon released the D7100), I tried Auto-ISO. I kept encountering a problem - I'd grab a shot in low light, and the D7000 would automatically hike the ISO. No Prob. But then, I'd move to a fully-lit, bright sunlight area and grab a few more shots. Upon entering LR for post, I discovered that the D7000 had NOT lowered the ISO back to where it had been before I took the low light shot.

So I've disabled Auto-ISO and when I need to raise or lower ISO, I do so at the amount I want and no more.

Works better for me.

Delderby Loc: Derby UK

Perhaps there is a fault in your camera's firmware?

JaiGieEse Loc: Foxworth, MS

Could've been. But I've updated the firmware at least once, perhaps twice. Will have to try again and see what occurs.