what controls the f stop the lens or the camera

[0bli0]

TV stands for timed value. yes Canon is the primary vendor who uses this to stand for what many call 'shutter priority' - you set the shutter speed and based upon the light metre and your ISO setting, the camera then sets the aperture.. funny thing is, Ricoh calls TV mode exactly what was described above - a mode for capturing images from TV or monitors without black bars.

 

[jann1033]

ok now that we know tv doesn't mean television ,,,\\here is what is happening


outside ( some what overcast today but it 's 11 in the morning here so there is light out side)at 28mm the shutter won't go above 200 and the f is between 10-20 ( iso 100 or 200) at 50mm it is not focusing( see OTHER thread of mine about that ) then finally focuses at 200 and 5.6, anything above 200( to 4000) just blinks "5.0", anything below 200,f goes in increments to 30ish then blinks. at 80mm is roughly the same..if i set iso at 800 i can get the f to 3.5/shutter 1000 at 80mm if in av mode but not tv..., a little larger aperture in other mm also at 800.so basically if i want to use any f but 5.6 i have to use 800 iso...that just doesn't seem right( inside at av/tv/800 iso it just blinks, can't get it to take anything at all but it isn't focusing either so maybe that has something to do with it) on auto inside it takes it with flash at 60 f4, on p with flash up, it doesn't lock focus or take it at the same setting

maybe the chip doesn't work??? anyone know exactly what the sigma rechipping for rebel xt does?. it seems like something is not communicating between the lens and camera to me but since i don't really know how it communicates i'm at a loss..

( the point about the picture was a misunderstanding...i thought steve meant 80mm and that's what the picture was taken at...)

 

[Anewman]

outside ( some what overcast today but it 's 11 in the morning here so there is light out side)

OK before we go any further.

What exact settings are you using?
Any extra info may help, like metering mode/focus points/etc...

ok now that we know tv doesn't mean television ,,,\\here is what is happening


outside

at 28mm the shutter won't go above 200 and the f is between 10-20 ( iso 100 or 200) at

I really dont know what setting you are using? GREENBOX? AV? TV?

50mm it is not focusing( see OTHER thread of mine about that ) then finally focuses at 200 and 5.6, anything above 200( to 4000) just blinks "5.0", anything below 200,f goes in increments to 30ish then blinks.

OK that blinking RED "5.0" means you have maxxed out the APERTURE(at that focal length) and there is still not enough light or TOO MUCH light to get a proper exposure, now it sounds like you are using TV.

Look at the exposure meter at the bottom of your viewfinder, is it all the way LEFT or RIGHT?

at 80mm is roughly the same..if i set iso at 800 i can get the f to 3.5/shutter 1000 at 80mm if in av mode but not tv..., a little larger aperture in other mm also at 800.

Ok you raised ISO to 800 which is like letting in more light, Now I assume you did not have enough light at 50mm(above).

so basically if i want to use any f but 5.6 i have to use 800 iso...that just doesn't seem right( inside at av/tv/800 iso it just blinks, can't get it to take anything at all but it isn't focusing either so maybe that has something to do with it) on auto inside it takes it with flash at 60 f4, on p with flash up, it doesn't lock focus or take it at the same setting.

OK you lost me, but I am trying to understand.

First off if you want to use ANY F but 5.6 you need to have the right amount of light and the right shutter speed. One can not just choose a shutter speed and aperture if the amount of available light does not allow for proper exposure. So maybe with the amount of light you had available and the shutter speeds you were selecting(if in TV mode), ISO 800 was the only way to obtain a proper exposure.
When you go inside with those same settings it now BLINKS because the amount of light Decreased so you can no longer get that proper exposure.
This has nothing to do with focus, the camera will not take that picture, it will just blink on the settings that have been maxxed out.

maybe the chip doesn't work??? anyone know exactly what the sigma rechipping for rebel xt does?. it seems like something is not communicating between the lens and camera to me but since i don't really know how it communicates i'm at a loss..

( the point about the picture was a misunderstanding...i thought steve meant 80mm and that's what the picture was taken at...)

Does it focus in full auto?

 

[Kelly Grannell]

Jann,

I think there is something wrong with the Sigma. Either the chip gone bad or the some internal mechanism within the lens is messed up.

I accidentally burnt my chip this weekend (my teach' Sigma 17-70) but removing the lens before turning off the camera. I guess I shorted it and the chip is now zapped. (Sigma Canada confirmed that the chip is zapped, the re-flashed it, now it works just like new again).

 

[jann1033]

Jann,

I think there is something wrong with the Sigma. Either the chip gone bad or the some internal mechanism within the lens is messed up.

I accidentally burnt my chip this weekend (my teach' Sigma 17-70) but removing the lens before turning off the camera. I guess I shorted it and the chip is now zapped. (Sigma Canada confirmed that the chip is zapped, the re-flashed it, now it works just like new again).

i think after trying every setting under the sun this morning i am leaning in that direction also... especially since i had a problem with the same lens/old camera also ...I'm waiting for a check so i can get the new lens which i should have within a few days so if the same thing happens with that one then it's the camera or moi but the chances are better for the lens ( i think even i would have a challenge messing up that bad that many times...what are the chances i 'd never hit the right settings just by accident even an orangutan could do better )

 

[Anewman]

EDIT = NEVERMIND my mistake

 

[Anewman]

Nevermind, I always use manual and just checked AV and TV modes. It is EC not a level meter in those modes.

Bottom line, the lens seems to be working if you are within correct exposure settings or AUTO.

Unless I am missing something.

 

[jann1033]

OK before we go any further.

What exact settings are you using?
Any extra info may help, like metering mode/focus points/etc...



Does it focus in full auto?

not always, it doesn't lock focus.

the tests i was doing was outside at 11 am...plenty of light so it shouldn't have to be at 800 iso to take a picture . it did basically the same thing in av or tv and any iso lower thanl 800...again it's the middle of the morning, outside.

then i went inside and it worked on auto but not on the p mode with the flash up at the same settings that it had on auto a second before in the exact same situation

 

[Anewman]

not always, it doesn't lock focus.

the tests i was doing was outside at 11 am...plenty of light so it shouldn't have to be at 800 iso to take a picture,

Well that depends on the shutter speed you are trying to use.

it did basically the same thing in av or tv and any iso lower thanl 800...again it's the middle of the morning, outside.

You made the choice to go upto ISO 800, you could have slowed shutter speed to reach a proper exposure as well.

then i went inside and it worked on auto but not on the p mode with the flash up at the same settings that it had on auto a second before in the exact same situation

"It worked on auto", and then you switched to P mode with the FLASH UP. Did you know that with the flash up max shutter speed is 1/200th, and in AUTO mode the ISO is set by the camera so it could have been 100-400(max). Switching to P mode could use ISO 800(if that is what you set last) so they may not have been EXACLTY the same settings.

This following was what finally drew the picture for me...

at 50mm it is not focusing( see OTHER thread of mine about that ) then finally focuses at 200 and 5.6, anything above 200( to 4000) just blinks "5.0", anything below 200,f goes in increments to 30ish then blinks.

In TV mode you SET the shutter speed and the ISO, all the camera is going to set for you is APERTURE, and if the camera feels that accebtable exposure can not be reached it will BLINK where its adjustment can go no further. It has nothing to do with "focus".

When you went down to 1/200th it would allow you to take the picture with the lens WIDE OPEN, as you slowed the shutter speed down further it adjusted the Aperture until it maxxed out and then started blinking.
The lens focused the entire time you were within that range, correct?

 

[handicap18]

Has Canon always used Tv for Shutter Priority, even with their film SLR's?

To me it makes sence that S means Shutter and takes up less room than Tv (Time Value?!?). It took me the LONGEST time to figure out the Tv and Av settings on my Canon digital P&S were for shutter and aperture priority. I was used to plain ol S and A. I always got confused when I went to take small video clips and wouldn't get anything on Tv. But then again, I am just a lowly Nikon user.

 

[0bli0]

yes, i do know from experience on the elan 7e and the 1v, it has TV and AV modes.

 

[caniswolfie]

I don't know if they always used Tv for their shutter priority mode, but I have a manual (and the camera) for a Canon AE-1 (which didn't have a shutter priority mode). In the manual they always refer to the shutter speed as such and I don't see anywhere where they refer to it as Tv or Time Value. Maybe they decided to call it that when they released on their first camera to have the function and it stuck. *shrug*

 

[jann1033]

i know my film rebel dial was set up exactly like this one except the digital adds a flash off to the auto modes .... course now the question is why in hades am i having such a hard time with the digital since i had no problem using the film for yrs????????????????????????????????????????????