[narual]

I guess I'm a bit suspicious how well two variables can be set at once.

Well, Program mode and for that matter, full on green mode seem to do a pretty decent job... why would pegging the ISO to a specific number cause problems?

[wildman]

why would pegging the ISO to a specific number cause problems?

Certainly it can - my question is for any given amount of light (exposure) and ISO it could be accomplished either by, say, a large aperture and a fast shutter or a small aperture and a slow shutter. How does the logic in the camera decide this choice without the intervention of the photographer?

But as I say I have not worked with it so maybe I'm completely misunderstanding exactly how it works.

[tuco]

I don't think Canon and Olympus allow exposure compensation in M mode, but Nikon does (it may also be camera dependent). That would kick an attempted pseudo-TAv implementation's usefulness down a couple notches.

I can't say what Canon or Olympus does. But if your think about it, EV comp in manual mode can be a redundant option. What does it do? It slows or increases your shutter speed. You are in manual mode! You have to set the aperture/shutter speed to get a good exposure either by trial-n-error or looking at the exposure meter in the viewfinder while adjusting either one of those settings. So adjust the shutter speed up or down a stop or fractions thereof as indicated by the exposure meter to get the same thing. Perhaps even faster than setting the EV comp.

[BrianR]

How does the logic in the camera decide this choice without the intervention of the photographer?

Sv seems to work based on the Program Line, which is marginally adjustable on some models so you can have it aim for Small DoF, Large DoF, Fast Shutter, MTF, etc.

I don't see much use for Sv mode personally. On a camera that has a dedicated ISO button to let you change sensitivity on the fly when combined with one of the wheels, it's only marginally different from P mode.

---------- Post added 06-19-14 at 02:37 PM ----------

I can't say what Canon or Olympus does. But if your think about it, EV comp in manual mode can be a redundant option.

It's not redundant if you have an M-mode with Auto ISO unless you're happy relying 100% on the cameras metering decision or relying on workarounds using exposure lock. Without it, you aren't emulating TAv mode (whether that's important to someone or not is another question).

With no Auto ISO in M-mode, EV comp biases the meter on pentax cameras (not all have EV comp in M-mode though). Yes, it's no different from just adjusting the shutter or aperture to over or under expose what the meter indicates, but it can still be a useful option to some people if that's the way they prefer to think.

[narual]

Certainly it can - my question is for any given amount of light (exposure) and ISO it could be accomplished either by, say, a large aperture and a fast shutter or a small aperture and a slow shutter. How does the logic in the camera decide this choice without the intervention of the photographer?

But as I say I have not worked with it so maybe I'm completely misunderstanding exactly how it works.

"As in Program mode, you can select which program line the K-5 should abide by when determining these variables: normal, higher shutter speeds, shallow or deep depth of field, best MTF value, or an automatic selection between these types. "

[Lowell Goudge]

No, not directly. Some companies aloow ISO to be set to auto in M mode (illogical but there you are) so you can achieve the same kind of results.

No other company has hyper-program (P mode with access to Tv and Av just by scrolling the wheels). I might be wrong but I think that no other companies have program lines such as MTF.

Crazy as it sounds you can do it on the Q also

[blackcloudbrew]

I took me a long time to figure out Sv mode, I use it shooting Xmas lights at night as I have to really control ISO, Sv mode is perfect for that over all others IMHO.

[wildman]

Sv seems to work based on the Program Line

As in Program mode, you can select which program line the K-5 should abide by

OK got it...will look into Sv a bit further and see what it might have to offer.

As to my original question it looks like while TAv is not entirely exclusive to Pentax it does seem to be the most direct, explicit and, perhaps, complete implementation of it so far as I can determine. I asked because I have found it personally such a logical, transparent and useful mode that I just thought some variation of it would be more or less as standard as Av and Tv on other makes - but apparently not. Not being a gear head I don't keep up on such issues and what other makes are doing so I asked.

Anyway thanks for your posts they have been helpful.

[narual]

Not sure *why* it isn't a mode on other cameras, but maybe Pentax has a patent on it or something. It's very useful, for sure. My photos of things like concerts (people moving quickly in questionable lighting) have gotten much, much better since I started using TAv mode.

I don't think I've run into any situation that's made me want to use SV mode yet.

[wildman]

maybe Pentax has a patent on it

Or perhaps because it's precisely not patentable. It's so obviously simply a logical closing of the circle of shutter to aperture to sensitivity made possible by digital. The big boys want product differentiation not something anyone could implement. Who knows what goes on up in corporate?

My photos of things like concerts (people moving quickly in questionable lighting) have gotten much, much better

I hear you. I recently covered a fund raiser at an Art museum of corporate and foundation supporters of the museum. Between the K5 in TAv mode with a superzoom, letting ISO roam from 80 to 12800, shooting in RAW, processing in ACR+Photoshop there was no situation that I couldn't get at least decent results in anything from wide angle to close up all in one mode with no lens change - marvelous. It must be said that an Art museum is, of course, well lit with no hot spots or deep shadow so everything was thankfully available light.

TAv really could be called "Street" mode - it would be perfect for that.

[emalvick]

I see the usefulness of TAv mode. I'm not sure I care much at whether Pentax somehow would have worked an auto-iso into the M mode, but logic-wise, TAv sounds more sensible.

I never fully understood the advantage of Sv mode over just setting a fixed ISO in P mode. I guess you can customize both modes separately giving a bit of an advantage. However, one could add an additional User mode in its place to allow a user who wants that difference to program it while letting other users perhaps do something different. That's just an opinion, however. I never remember to use Sv mode (usually using P to implement that type of use), and I wish I would remember to use TAv more often. I tend to use M and manually adjust the ISO to get what I want (or the other settings). Some of this comes from starting with a K10d many years ago and avoiding TAv because of the poor ISO performance of that camera. With my K5, TAv is fantastic (I just don't think to use it). I wouldn't care, however, if it was built into Manual (whether it's technically right or not).