TAv mode — do you use it?

I don't own a Pentax, but the TAv mode seems very useful to me, since it lets you control both DOF and motion blur at the same time. It's more convenient than full manual since you don't have to fiddle with setting the third variable, ISO, and since it allows exposure compensation.

Nikon also has the mode implicitly with auto ISO in manual. Apart from that I don't know of any brands that has the mode. Om my OM-D I can use auto ISO in manual, but I don't have exposure compensation.

To me TAv (and its Nikon equivalent) seems like the most useful mode of them all — so how much do you use the mode?

I use it quite regularly - it's a good tool to have.  A disadvantage is that you can overexpose if you're not careful... e.g. set 1/125 and f/8 and forget about it, but if the sun comes out you might need ISO 50 or 25 and as those aren't available the shot is overexposed by 1 or 2 stops.  Yes there is a small warning flashing somewhere but it's easy to miss if you are concentrating on framing the shot.  I use TAv mode most for shooting moving things (like kids) in relatively poor light - so I'd set (say) 1/500 sec and lens wide open, and let the ISO float as it wants.  That works very well.

Best wishes

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Mike
http://www.pentaxphotogallery.com/artists/mikeward

Whenever light is not sufficient I use TAV – in fact I use it a lot, but like somebody else said you should take care that the light condition has not changed to the brighter side, because then your TAV settings may result in overexposed pics!

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I find it's a good mode to use where the light is changing quickly and not entirely predictably (e.g. stage lighting for rock / pop concerts).

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Cheers,
sfa

I always use TAv for wildlife shots. I need high shutter speeds subject motion and sometimes camera shake with a long lens. Most lenses are sharper stopped down, and certainly DOF with a long tele is very limited at wide apertures. Depending on whether I point the camera into the woods or a sunlit meadow, ISO's can vary as much as six stops.

I also use TAv in low light. In dim conditions I like to maintain 1/20-1/30s minimum with primes in the 28-50mm range, to control shake . Some lenses like the FA 50 are much better stopped down once or twice, or sometimes you need more DOF. If I let the camera determine the shutter speed, it will usually go higher than I want, then the image gets noisy.

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Dan

I use it a lot for wildlife – with a DA*300mm I like to keep the shutter at 1/250 or faster and f stop around 5.6. It is very useful in poor light.

When i changed from the K-r to the K-30, i thought i wouldn't use it a lot.

I was wrong. It is VERY useful, but i only use it in low light, or to shoot something moving fast (like a kart) in not-so-bright daylight...

I also noticed i started to use it more after i got my F 50mm 1.7. I choose TAv, dial in F2 and 1/60th and shoot away.

I wouldn't say that TAv is the most useful mode but it certainly does have its uses.

It's a fundamental principle of digital photography that you should always use the lowesr possible ISO to maximise DR and minimise noise.  Whenever possible, therefore, I use an exposure mode that lets me choose ISO.  For example, if I want control of DOF (whether narrow or wide) I use Av and let the camera determine shutter speed.

It's when the light gets too low, or if I need to control both aperture and shutter that I go to TAv.  How often this happens is obviously personal; for me it's under 5% of all the shots I take.

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Gerry
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First camera 1953, first Pentax 1985, first DSLR 2006
http://www.pbase.com/gerrywinterbourne

I agree with you that the lowest possible ISO value is almost always the most desirable. To me that's an argument for using TAv: Selection of ISO value is a no brainer, and therefore the variable best left for the camera to descide. It can safely assume that this value should be as low as possible. Not so with shutter speed and aperture.

I think TAv can be useful in any light. Let's say you do street shooting on a sunny day. You want a shutter speed of 500 to freeze motion and ensure sharpness and an aperture of 11 for good DOF. TAv could then be very handy. Of course you should still watch the exposure and the ISO, but you wouldn't have to be changing the ISO manually all the time.

I'm much more comfortable with letting the camera control ISO (within user defined limits) than either shutter speed or aperture. Jay Maisel supposedly leavs his ISO at 1600 all the time for cinvenience since he thinks it's "good enough".

I suppose I use it mostly for indoor shooting, and I do so quite often.

I think it is a mode that reflects how digital photography works, as opposed to a film-based logic.

I also use it a lot to test for manual flash work. I see what ISO it gives me with the aperture/speed I want to use, then go back to manual and just use a suitably lower ISO, compensated by flash. There's probably a more intelligent/technically literate calculation I could use, but I find it just works and it is simple and easy.

I would have thought more companies would imitate TAv, but they don't seem to. Beats me why.

Ian

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http://picasaweb.google.co.uk/iangoldring

Oh, and also for fast moving stuff – like others seem to it seems.

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http://picasaweb.google.co.uk/iangoldring

I use it frequently in low light situations where my primary concern is the capture itself and not the amount of noise.  That said, you can affect the nature of the output by limiting the auto-ISO range.  With the K20D I would limit at 800, 1000, maybe 1600.  With the K5IIs, I've bumped that way up, as high as 12800 (in a dark bar), and was pleasantly suprised with how acceptable the results were.

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Doug
http://adairphotos.zenfolio.com/
http://www.pentaxphotogallery.com/dougadair

If my subject moves and ISO 80 doesn't give me enough speed, I'm always in TAv mode. It's very practical!

In Pentaxland, exposure compensation works in all modes, including fully manual: press the green button and aperture and shutter speed go to whatever P mode would have chosen for you, taking exposure compensation into consideration.

Seriously, doesn't Canon have auto Iso!?

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Miles Green
Pentaxian with chronic LBA
Corfu, Greece

If you want to shoot wide open in TAv, you might as well use Tv mode with auto ISO. That way you won't get overexposure in Tv mode, as the program line will just stop down for you if it hits the lower ISO limit and otherwise the behaviour will be identical, i.e. wide open aperture at elevated ISO values.

On the other side, I suppose it's an advantage of TAv mode to be able to stop down quickly just by twiddling the rear (aperture) dial, as opposed to turning the mode dial from Tv to TAv and then twiddle the rear dial.

Regards,

--Anders.

I always use it when I want to catch some acts and dont find enough time to use M mode.

but almost results are overexposure!/

I shoot mostly macros, mostly of usually fast-moving insects like butterflys, for which I use an autofocus  200mm macro lens. I most want to control f-stop for depth of field and shutter speed for motion control. There's little depth of field available at high magnifications, so I usually set the camera to f20 or thereabouts. I move, the insects move, and there's often a breeze blowing, so I often set the shutter faster than 1/300. I limit ISO to a max of 6400, but I shoot mostly in bright light, often with flash fill, so the ISO usually winds up lower. I use matrix metering and IS is always on. It all works very well, instantly adapting to changing surroundings and backgrounds. If my subject is unusually bright or dark it is easy to dial in exposure compensation without having to remove my eye from the viewfinder. On the rare occasions when exposures are off it is always my fault, not the camera's (currently a K5).

Yes, its very useful for indoor shots where you need both variables pinned down.   Because it reduces 2 of the 3 degrees of freedom the exposure program has, you are limiting the camera to 1/3 stops + / - so it can over / under expose a bit.   I tend to hedge this by shooting RAW+ ( because I'm lazy ) and under exposing by 1/3 stop if I see it going that route.   I can fix underexposed shots easier than blown highlights.

But to be honest. with the K-5's high ISO performance, I also use shutter priority, and let the camera ramp up the ISO's.   Kids at a birthday party, for example, jacked up on cake, gummy worms, and frosting, require a predictably high shutter, so I'll rig it for "kids bouncing off walls" mode that way.

You end up with a similar end result, but giving the camera more latitude to play aperture and ISO against each other can give better exposure solutions, IMO.

I find it useful and use it occasionally.

-- Bob
http://blog.trafficshaper.com
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That's not how it works. TAv doesn't choose the lowest ISO; it chooses the "right" ISO as calculated by the camera's exposure meter.  So there are three possibilities: (1) the aperure and shutter you've set happen to need exactly the lowest ISO your camera has, in which case exposure will be right and you get the lowest possible ISO; (2) the A and S you've chosen need ISO higher than the camera's lowest, in which case exposure is still OK but you aren't using the lowest possible ISO; (3) the A and S you've chosen need a lower ISO than the camera can give, in which case you get the lowest possible ISO but the shot is overexposed.

Yes, this is an example of what I said "if I need to control both aperture and shutter".

We all make our own compromises.  Wasting DR for convenience isn't one that I'll ever make.

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Gerry
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First camera 1953, first Pentax 1985, first DSLR 2006
http://www.pbase.com/gerrywinterbourne

I had never ever used it until the RNZAF airshow. Perfect  setting it turned out

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K-5 some Len

Yes, I've understood that all along. My point is simply that TAv mode is a very useful mode, and indeed to me seems like the most useful of them all, because it lets you control DOF and motion at the same time, while you leave the no brainer — the noise control — to the camera.