TV priority question

dane.dawg · 11-25-2012, 05:18 PM

I use TAV mode 90 percent of the time on k-5 and DA* 300mm but today i used TV mode set to 1:1000 and it chose f11 at 640 ISO.. Why would it not choose a higher aperture and bring the ISO down.

**Ex Finn.** · 11-25-2012, 05:45 PM

Sounds like the camera figured that this person is shooting BIF. Long lens, high shutter = freeze movement and give some depth of field for better chance of getting the focus right. Also the ISO is of no concern with the K5, at that level. Just my thought.

**jatrax** · 11-25-2012, 05:50 PM

In Tv mode the ISO is not changed by the camera, only in TAv mode. Or am I missing something?

**Ex Finn.** · 11-25-2012, 05:53 PM

In Tv you only control shutter, camera controls ISO and aperture. There is some biasing going on however.

dane.dawg · 11-25-2012, 06:03 PM

I get what you are saying Ex Finn, but i thought it would pick f8 /ISO320 or something along those lines..

**jatrax** · 11-25-2012, 06:03 PM

Doesn't work that way on mine. Maybe I have something set different? Front e-dial changes shutter speed and rear e-dial changes ISO. Camera changes aperture.

derekkite · 11-25-2012, 06:19 PM

The manual says that it will change aperture in response to metering. If you set your edial to front = shutter, back = iso, green button =iso auto, you can set iso or let it float. In auto it will change only if the aperture is wide open.
I think av mode is similar but shutter speed is adjusted.
You can set the iso range top and bottom values. Say you set the bottom range to 320, tv at 1000 to catch motion, iso auto, then as you shoot the aperture would adjust to the metered light. If it is dark aperture goes to max, iso starts creeping up. If bright the iso goes to min and aperture closes. If you start with a base iso that matches conditions this might work.
The reason iso was high was because it was not auto.

derekkite · 11-25-2012, 06:23 PM

I think

Second thoughts, you would want to set the iso range low, 80 say, so that as light increases it drops the iso instead of stopping down aperture. That would tend to set the lens wide open if, for example, you are shooting a bird in flight against the sky. If your lens can handle wide open, this would work.

I may be reading your mind, but I suspect you are trying to keep shutter speed high enough but have the rest of the settings follow without having your iso go too high. I found with TAV mode that I ended up in practice with too many high iso shots with the attendant loss of quality because I wasn't quick enough to twiddle the two dials to find the sweet spot. If you are following a bird in flight against trees or mountain backgrounds, it is impossible to twiddle. Auto iso in tv mode might work ok, and you can bias towards stopped down aperture by raising the bottom limit of the auto iso range.

Having lenses that need stopping down to give any quality at all, I've tended towards AV mode and got reasonably quick at adjusting iso to get a shutter speed that I want. In practice I end up with lots of movement blur but no CA. I remind myself that shooting birds is one of the most challenging subjects to not become disheartened.

dane.dawg · 11-25-2012, 06:58 PM

LOL, im a total newb, my iso was not on auto..

11-25-2012, 05:18 PM	#1
dane.dawg Veteran Member Join Date: Aug 2011 Location: B.C. Photos: Gallery Posts: 1,436	TV priority question I use TAV mode 90 percent of the time on k-5 and DA* 300mm but today i used TV mode set to 1:1000 and it chose f11 at 640 ISO.. Why would it not choose a higher aperture and bring the ISO down.

11-25-2012, 06:23 PM	#8
derekkite Pentaxian Join Date: Sep 2011 Location: Nelson B.C. Posts: 3,782	I think Second thoughts, you would want to set the iso range low, 80 say, so that as light increases it drops the iso instead of stopping down aperture. That would tend to set the lens wide open if, for example, you are shooting a bird in flight against the sky. If your lens can handle wide open, this would work. I may be reading your mind, but I suspect you are trying to keep shutter speed high enough but have the rest of the settings follow without having your iso go too high. I found with TAV mode that I ended up in practice with too many high iso shots with the attendant loss of quality because I wasn't quick enough to twiddle the two dials to find the sweet spot. If you are following a bird in flight against trees or mountain backgrounds, it is impossible to twiddle. Auto iso in tv mode might work ok, and you can bias towards stopped down aperture by raising the bottom limit of the auto iso range. Having lenses that need stopping down to give any quality at all, I've tended towards AV mode and got reasonably quick at adjusting iso to get a shutter speed that I want. In practice I end up with lots of movement blur but no CA. I remind myself that shooting birds is one of the most challenging subjects to not become disheartened. Last edited by derekkite; 11-25-2012 at 06:42 PM.

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11-25-2012, 05:45 PM	#2
Ex Finn. Site Supporter Join Date: Nov 2007 Location: Southern Maryland. Espoo. Kouvola. Photos: Gallery \| Albums Posts: 7,975	Sounds like the camera figured that this person is shooting BIF. Long lens, high shutter = freeze movement and give some depth of field for better chance of getting the focus right. Also the ISO is of no concern with the K5, at that level. Just my thought.

11-25-2012, 05:50 PM	#3
jatrax Site Supporter Join Date: May 2010 Location: Washington Cascades Photos: Gallery \| Albums Posts: 12,991	In Tv mode the ISO is not changed by the camera, only in TAv mode. Or am I missing something?

11-25-2012, 05:53 PM	#4
Ex Finn. Site Supporter Join Date: Nov 2007 Location: Southern Maryland. Espoo. Kouvola. Photos: Gallery \| Albums Posts: 7,975	In Tv you only control shutter, camera controls ISO and aperture. There is some biasing going on however.

11-25-2012, 06:03 PM	#5
dane.dawg Veteran Member Join Date: Aug 2011 Location: B.C. Photos: Gallery Posts: 1,436 Original Poster	I get what you are saying Ex Finn, but i thought it would pick f8 /ISO320 or something along those lines..

11-25-2012, 06:19 PM	#7
derekkite Pentaxian Join Date: Sep 2011 Location: Nelson B.C. Posts: 3,782	The manual says that it will change aperture in response to metering. If you set your edial to front = shutter, back = iso, green button =iso auto, you can set iso or let it float. In auto it will change only if the aperture is wide open. I think av mode is similar but shutter speed is adjusted. You can set the iso range top and bottom values. Say you set the bottom range to 320, tv at 1000 to catch motion, iso auto, then as you shoot the aperture would adjust to the metered light. If it is dark aperture goes to max, iso starts creeping up. If bright the iso goes to min and aperture closes. If you start with a base iso that matches conditions this might work. The reason iso was high was because it was not auto.

11-25-2012, 06:58 PM	#9
dane.dawg Veteran Member Join Date: Aug 2011 Location: B.C. Photos: Gallery Posts: 1,436 Original Poster	LOL, im a total newb, my iso was not on auto..