Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
06-02-2008, 11:23 PM   #1
Veteran Member
morfic's Avatar

Join Date: Feb 2008
Location: San Antonio, TX
Photos: Gallery
Posts: 428
Sv and TAv

Why do we have those?

Isn't Sv just P after selecting an ISO (Less the "Hyper" part)?

and isn't TAv just M with Auto ISO?

what do Sv and TAv have that i couldn't get from the alternatives?

Is it marketing only?



06-02-2008, 11:44 PM   #2
Junior Member




Join Date: Mar 2007
Location: Oregon, USA
Photos: Gallery
Posts: 49
QuoteOriginally posted by morfic Quote
Why do we have those?

Isn't Sv just P after selecting an ISO (Less the "Hyper" part)?

and isn't TAv just M with Auto ISO?

what do Sv and TAv have that i couldn't get from the alternatives?

Is it marketing only?

Yeah, seems like Sv is a lot like P after manually choosing an ISO. However, TAv is different from M mode in that there is an EV comp control in TAv whereas M mode simply provides direct access to the three parameters.

I think having auto ISO in M mode might be confusing--not only would it no longer be M mode, but you'd need to have the EV comp functionality show up somewhere. Also, there's more ambiguity in the behavior of the green button if you just had M mode with auto ISO.

On top of all that, the flash behaves differently in M and TAv modes--again, having separate modes is a good way to separate the behaviors.

Bart
06-03-2008, 12:16 AM   #3
Veteran Member
KungPOW's Avatar

Join Date: Nov 2007
Location: Vancouver, Canada
Photos: Gallery
Posts: 1,702
I have SV set in the custom menu so that the fwd e-dail is program shift, and the rear dial is iso. The setting then acts allot like AV mode. It allows you to dial through the various T/A combos, and have direct control over ISO on the rear wheel.

The real diference between AV and SV though is the control over ISO. If the camera is set to Auto ISO, then it will select the "best" ISO for you in AV, but it will not it SV. So you can have auto ISO in AV mode, then swith to SV mode for manual ISO, then back to AV for auto ISO. No need to use the function key.

You can also have two different manual ISO's preset. one for AV, and one for SV.

And finally, in AV hitting the green buttton wil turn Auto ISO on.

I find TAV mode usefull when I am shooting available light, very close to the limit of the lens, and I want control over my DOF and shutter, but I do not want to go to full manual mode. And yes, it is M with auto ISO. But you do not need to go into a menu to change anything to auto ISO. And when you then switch to M mode, it will still have the same ISO settings as you had with AV and TV.

The very slight diferences between the modes is one of the things I really like about the K10D. It is also the reason I cringe whenever I read a review that slams the K10D/K20D for not having a dedicated ISO button.
06-03-2008, 12:17 AM   #4
Veteran Member
KungPOW's Avatar

Join Date: Nov 2007
Location: Vancouver, Canada
Photos: Gallery
Posts: 1,702
QuoteOriginally posted by bart_hickman Quote
Yeah, seems like Sv is a lot like P after manually choosing an ISO. However, TAv is different from M mode in that there is an EV comp control in TAv whereas M mode simply provides direct access to the three parameters.

I think having auto ISO in M mode might be confusing--not only would it no longer be M mode, but you'd need to have the EV comp functionality show up somewhere. Also, there's more ambiguity in the behavior of the green button if you just had M mode with auto ISO.

On top of all that, the flash behaves differently in M and TAv modes--again, having separate modes is a good way to separate the behaviors.

Bart
Great points, I forgot about how Ex comp functions between modes.

06-03-2008, 12:19 AM   #5
Veteran Member




Join Date: May 2007
Location: Tirana, Albania, South Europe, Planet Earth
Photos: Gallery | Albums
Posts: 621
Let me give you an example why it might help.

I'm shooting for fun my colleagues' football (the real one ) matches in the company's championship.

This is indoors, so it's dark. I have a k100d and a digital concepts flash, I think it's called 952pen or something like that. The flash tends to underexpose by about 1 or 1.5 stops.

So I need fast shutter speed of 1/180s to freeze the action, wide aperture (f/3.5 or f/4.0) to let more ambient light in and an exposure compensation of +1ev to +1.5ev.

So, if I use M mode I can't get ev compensation. In Av mode, the shutter is to low, in Tv mode the aperture is set to f/2.8, so it's difficult to get proper focused shots.

My best option now is sports mode. The camera sets the shutter to 1/180s or thereabouts, aperture to f/4.5-5.6, and I can use ev compensation.

TAv would be perfect though as I can set the shutter, aperture and ev compensation to my liking.

Don't forget that if you don't use one feature of the camera it doesn't mean that it's a marketing gimmick. It's like saying that most of the users don't need weather sealing so it's only a marketing gimmick .
06-03-2008, 12:31 AM   #6
Veteran Member
KungPOW's Avatar

Join Date: Nov 2007
Location: Vancouver, Canada
Photos: Gallery
Posts: 1,702
QuoteOriginally posted by Deni Quote
Don't forget that if you don't use one feature of the camera it doesn't mean that it's a marketing gimmick. It's like saying that most of the users don't need weather sealing so it's only a marketing gimmick .


Awsome explination!

But I really do believe that "pet mode" on the K100D is a marketing gimick!
06-03-2008, 01:14 AM   #7
Pentaxian




Join Date: Sep 2006
Location: Kaunas
Posts: 1,452
QuoteOriginally posted by KungPOW Quote
The real diference between AV and SV though is the control over ISO. If the camera is set to Auto ISO, then it will select the "best" ISO for you in AV, but it will not it SV. So you can have auto ISO in AV mode, then swith to SV mode for manual ISO, then back to AV for auto ISO. No need to use the function key.
Well, if you want to have manual ISO in Av mode, you just press OK, turn front e-dial and set desired ISO. When you want to go back to Auto ISO you press OK and Green button. No need neither to swith over to Sv mode nor use Fn menu.
Alternatively you can set up one of e-dials to control ISO in Av mode and control ISO directly with e-dial and green button. I use such set-up and effectively I get not an Av mode, but ASv mode
06-03-2008, 01:28 AM   #8
Pentaxian




Join Date: Sep 2006
Location: Kaunas
Posts: 1,452
QuoteOriginally posted by morfic Quote
Why do we have those?

Isn't Sv just P after selecting an ISO (Less the "Hyper" part)?

and isn't TAv just M with Auto ISO?

what do Sv and TAv have that i couldn't get from the alternatives?

Is it marketing only?

You know, if I would design camera I would redefine all modes

As we all know, exposure is defined by the combination of three parameters: shutter speed, aperture and sensitivity.

In film days you had fixed sensitivity and photographer was able to control exposure by adjusting two parameters: shutter speed and aperture. So, naturally it appeared two automated modes: shutter priority and aperture priority. You have one fixed parameter (sensitivity), one chosen by photographer and the third one, calculated by the camera.

In digital era Av and Tv became obsolete because sensitivity isn't fixed anymore and photographer can control exposure by changing all three parameters on the fly.

Therefore digital cameras should have had ASv, TSv and TAv modes instead of Tv and Av modes from the very beginning. Photographer chooses two parameters and camera sets the third one based on other two parameters.

Pentax probably were the first to implement those in K10D: You have TAv mode there and you can customize your e-dial to change ISO in Av and Tv modes, so effectively you get ASv and TSv modes instead.

Sv mode is redundant, it just duplicates Tv and Av with one e-dial set to control ISO.

So, would I design camera, it would have P, M, X, Bulb, TAv, TSv and ASv modes

06-03-2008, 06:07 AM   #9
Veteran Member
morfic's Avatar

Join Date: Feb 2008
Location: San Antonio, TX
Photos: Gallery
Posts: 428
Original Poster
Hey, thanks everybody, sounds good, in many ways, you must forgive a Canon trained head....
Having a few scenarios of switching back and forth between modes illustrated makes the brain reroute a few cells and go *click*
Between Bart, KungPOW and edvinas i read enough to know i will make them my own and just have one more thing to make shooting easier and one more thing to boast about, thanks.
06-03-2008, 06:08 AM   #10
Senior Member
joefru's Avatar

Join Date: Mar 2008
Location: South Louisiana
Photos: Gallery
Posts: 210
QuoteOriginally posted by KungPOW Quote
It is also the reason I cringe whenever I read a review that slams the K10D/K20D for not having a dedicated ISO button.
Right. Especially because of the fact that since firmware v1.1, we DO have an ISO button. It's labeled 'OK.'

The thing I don't like about Sv is that I prefer the 'PASM' labeling, so Sv makes me think of Shutter-priority.
06-03-2008, 06:23 AM   #11
Veteran Member
morfic's Avatar

Join Date: Feb 2008
Location: San Antonio, TX
Photos: Gallery
Posts: 428
Original Poster
Sorry, i feel compelled to add how much i love the Pentax ergonomics, K20D, how glad i bought thee! I wonder what else my Canon training has me miss, since i don't expect it and am not looking for it.
06-03-2008, 05:23 PM   #12
Pentaxian
Arpe's Avatar

Join Date: Sep 2006
Location: New Zealand
Photos: Gallery | Albums
Posts: 4,331
QuoteOriginally posted by Deni Quote
Let me give you an example why it might help.

I'm shooting for fun my colleagues' football ...
I too use TAv mode for sports, setting a fastish shutter speed and largish aperture, and keeping an eye on the ISO (when I remember, it got up to ISO4500 in the weekend before I noticed and opened up a bit!)
06-03-2008, 05:44 PM   #13
Loyal Site Supporter
Canada_Rockies's Avatar

Join Date: Nov 2007
Location: Sparwood, BC, Canada
Photos: Gallery | Albums
Posts: 9,142
QuoteOriginally posted by Arpe Quote
I too use TAv mode for sports, setting a fastish shutter speed and largish aperture, and keeping an eye on the ISO (when I remember, it got up to ISO4500 in the weekend before I noticed and opened up a bit!)
I grew up with manual only cameras, then graduated to Av and M, and now I just cannot get my head around the need to use Tv to keep my shutter speed up. I set the aperture, and the camera just jacks the shutter speed up to the maximum at that aperture, based on where I am pointing it and/or a cloud going by, or whatever.
06-03-2008, 05:47 PM   #14
Pentaxian
Arpe's Avatar

Join Date: Sep 2006
Location: New Zealand
Photos: Gallery | Albums
Posts: 4,331
That's what I used to do as well with my *istDS, but now I want higher speeds and wide apertures, but still let the camera figure out the exposure. With Av only I was never sure when the camera was going to stop altering the shutter and start altering the ISO, now I can control that. So basically I am controlling all 3 parameters with the 2 dials.
06-03-2008, 06:19 PM   #15
Veteran Member
KungPOW's Avatar

Join Date: Nov 2007
Location: Vancouver, Canada
Photos: Gallery
Posts: 1,702
So this thread got me thinking about the camera functions just a bit more then before. I started thinking about TAV mode and bracketing. In TV mode, bracketing varies aperture. TA, shutter speed is varied. Would it make sense that in TAV mode, ISO should be varied?

It turns out in TAV, ISO remains fixed, and shutter & aperture vary. Is this what I should have expected? Is there a way to bracket by ISO?

Maybe I should start a new thread, and not hijack this one.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
camera, dslr, iso, photography, sv, tav
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
TAv mode Howard2k Pentax DSLR Discussion 17 09-23-2010 01:30 PM
Night First use of the TAv function GordonZA Post Your Photos! 10 04-27-2010 03:49 PM
Tav mode amaruba Troubleshooting and Beginner Help 8 05-21-2009 11:59 AM
Tav function Vinfer Pentax DSLR Discussion 4 03-10-2009 08:11 PM
TaV mode Papou Photographic Technique 3 02-11-2008 10:03 PM



All times are GMT -7. The time now is 08:26 AM. | See also: NikonForums.com, part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top