Am I just being incredibly dense- AV/TV

January 8th, 2012
Feel free to say yes I am but you need to expand :P

I am trying, really, really trying to stop using the auto...what's the point in having a camera that does stuff if you don't use it to do the stuff?!

I have tried reading the manual. Let's just say that yesterday I thought I'd killed my camera because everything was coming out bright white.....then tried moving the +/- scale and that fixed it- so I guess that bit controls light exposure. (guess ) but that's what happens when I read the manual....it seems to not have been written in a language I understand. Russian would be easier.

So, yesterday I worked out what slow shutter speeds do. (Thank you to everyone who showed me their shots), today I did some more investigating and I guess it's the TV setting you use to set how long you want the exposure for . The longer the time it shows, the longer the time period the shutter is open for so the more info hits the inside bit of the camera ..... I think.

OK. I pratted about with the ceiling fan and got from completely blurred to completely stood still so think I understand that bit (right?)

Then I looked at AV......aperture priority.......aperture is how wide or narrow the focus is...... focal point....narrow focus = 1 thing in focus and blurry backgroun so one thing stands out , wide focus = less things blurry in background so less stands out..... (right?)

So I tried pratting with AV.

ummm, wth is the difference between AV and TV? There's a delay in the shutter,and the pictures with big number F looks the same as the pictures with small number F.

I know what the difference is in theory but in reality I'm thinking I'm missing something.

Please feel free to berate me, call me dense etc so long as you explain why I"m being dense.
January 8th, 2012
OK...for what it's worth....the numbers of your f stops (av) are counter intuitive. i.e. the smallest number actually opens the aperture the widest and the biggest number opens the aperture to the smallest setting. So to get the same amount of exposure you need to vary both your aperture and your time. As the aperture gets bigger (smaller number) then the time gets shorter.

Lowest aperture numbers (i.e. widest apertures) have a more minimal depth of field than higher ones.n (so they give you that blurry background)
January 8th, 2012
This might help!
January 8th, 2012
Whoa slow down sister........

Take a breath... and relax as I feel you are going too fast and confusing yourself. :)

No I don't think you are stupid/dense or any other word you may use to belitte yourself.

Think of them like this:

TV is shutter speed. Shutter speed is how fast you can stop an image. i.e water flying through the air.

AV is the apature: how blury you want the image. the lower the number the blury the image.

Do yourself a favor and just stick with AV and play with that. Sit back and take 40 photos of the same subject changing the AV and then look at the results. Once you understand what it does to the image the worry about the other stuff.

January 8th, 2012
@voodoochild I think we have the same camera manual.... and thank you because I have never understood this either.
January 8th, 2012
AV = Aperture Value (size of the hole in the lens that the light passes through)
TV = Time Value (the time that the shutter is open)
January 8th, 2012
@swilde :) I understand it, which is why I said I understand the theory. I'm not understanding the reality. lol.Thanks though :)
January 8th, 2012
@shadesofgrey It does, a little, I get the difference in the what they do, but I can't see any difference on the actual shot. I think.
January 8th, 2012
@agima lol, that's me :)

In real time I've been trying to work this out for over 20 years. What happens is that I try to work it out and can't so go back to auto....so this time I'm asking other people which is a new thing for me lol.

My problem is arising because I cannot see any difference between a picture taken using TV and one taken with AV. When I take the shot with a delayed time (TV) there is a delay in the shutter finishing it's job....so yes, I get TV. However when I change the F stop ...get a higher number F , I also get a delayed time for the shutter to do it's job so that's the same as TV. The only difference seems to be that I'm unable to alter the F in TV. (Which I probably could if I could understand the manual lol.)


I took a whole series of pictures in AV. I can see no difference in them no matter how high of low the F is ....the only difference occurs when my hand shook as I wasn't using a tripod and there was a time delay on the shutter.
January 8th, 2012
@corymbia thank god.
January 8th, 2012
@sburbidge :) at least I know I understood that bit. However when I alter the F on AV , the TV changes automatically.
January 8th, 2012
@voodoochild Do me a favour.

Take a photo in AV mode at the lowest number possible. The photo has to have a foreground, middle ground and background.

then change the AV setting to as big a number as you can get, then take the same photo.

The subject should only be about 1 meter away.

Then show me the results and I can explain how it works.
January 8th, 2012
@agima with pleasure :) Thank you :)
January 8th, 2012
@voodoochild cool. I took forward to the results.
January 8th, 2012
Try shooting something farther away than your ceiling fan, like a landscape. As you stop down the aperture, you will see a difference in how much you are able to get in focus. The reason the shutter changes is because the amount of light needed increases as the aperture gets smaller (number gets higher)...To really see a difference you need to have something relatively far away (not like a mountain range miles away....) but have a subject in the forground and a decent amount of space behind them. As the aperture gets smaller (number bigger) the more of the background is also in focus (DOF)...AV allows you to select the aperture and tells the camera to select the shutter speed, ISO and other factors that allows you to get the "correct" amount of light to make the picture show up....maybe that helps some?
January 8th, 2012
@voodoochild

To be able to see the difference in a shot when you change the AV number, the picture needs an item in the foreground (close), middle-ground, and distance.

When your number is small, you can only focus on the item in the foreground (think bokeh shots). As the number gets bigger you can get the middle-ground and foreground in focus.

You will need a big number to get close item and distance in focus (think landscape shots).

If your picture only has a single item in it, you may not be able to see the difference when you change the AV number :)
January 8th, 2012
@agima lol





the only difference I can see is a fuzzy foreground with the high f number. Please excuse slightly different view, I thought I'd returned to exactly the same spot after changing AV.
January 8th, 2012
@shadesofgrey ah I've got it. By george she's got hahahaha.
TY.

I think . lol.
January 8th, 2012
@voodoochild @shadesofgrey

Can you do it again with the dog 3/4 closer to the camera and put it off to the right.?

the closer the subject is to the lens the greater the affect.

January 8th, 2012
Here is an example that I just took of the difference between f2.8 and f22 on AV mode.

January 8th, 2012
@agima I can see it now, TY. low f, background sharp, high f background blurred yes?

Possible lightbulb moment

In AV the background is sharp or blurred but main object sharp. In TV main object can be blurred or sharp ( just thinking of the light shots and scenery shots and the fan rotor blades.) So even though both employ a lag on the shutter , the difference is what happens to the main object?????

So if I were trying to display motion I'd use TV and if I were trying to display distance I'd use AV ..... I think ?
January 8th, 2012
I just thought I'd add that I did most of my learning to photograph in low/no light conditions (underground). This is frustrating as it's really hard, but it forces you to understand what the settings are doing. Perhaps have a play at night?
Having said that - that's probably bad advice as you do end up with lots of failed shots which can be quite depressing!
January 8th, 2012
@voodoochild Close.

Let not talk about TV mode at the moment until we get AV sorted? Cool?

Do not confuse the two. :)

AV mode has two main purposes.

1) To give you the ability to blur the background. Why would you blur the background?? So you can separate the subject from the background. If you look at my example above you can see in the bottom photo the bottle really stands out. The background does not distract from the main subject.

2) To allow more light into the lens so you can take photos in low light without having to use a flash.

What actually happens in the camera is that when you have a higher F stop (AV number) you shrink the amount of light that comes into the lens. In the same way your eye closes when someone shines a light into our eyes.

When you have a smaller F stop the len is wide open and allows the most possible light in, so you can see in the dark. ;)
January 8th, 2012
@cavemonster are you a mole.. he he he.... I totally agree. I must prefer to take on something hard and then when you have to do something easy, it is easy.
January 8th, 2012
@agima my problem was trying to work out what the difference was between TV and AV because at first they seemed the same when I looked at the picture. I was trying to understand why both settings were there if they both did the same thing.

I think I was not seeing a difference because my subject in AV was too close and I was hearing the time delay in the shutter click in both TV and AV and interpreting that incorrectly....so I'm not trying to confuse myself and run before I can walk, but trying to understand why there's walking and strolling- both could look the same but they aren't.

Not trying to be awkward. I know that when I don't understand something ,in this case why there was AV and TV. I will never get past that point , no matter how well I understand AV.

ie Why take the easy path ? :P (Not on purpose lol)
January 8th, 2012
@voodoochild my point is how can you understand the difference between the two if you do not understand them interdependently?

Once you understand AV I am happy to explain TV, but I can not explain them both at the same time. :D

January 8th, 2012
Aperture (size of lens opening) controls the depth of field (% of view that is in focus).

Shutter speed controls the amount of motion blur.

If you make the aperture smaller (less light coming through), you need to slow down the shutter speed (open longer) to compensate. And if you make the aperture wider (more light) then you need to speed up the shutter so it is open a shorter time.

So if a good exposure is f/8 at 1/60th, and you want more background blur (wider aperture), you could change to f/5.6 and you'd need to change the shutter to 1/125th (faster) to keep the overall exposure correct.

Here's where Av and Tv come in.

In manual mode you'd have to adjust both aperture and shutter speed and calculate in your head how to change each.

In Av mode, you turn a knob which adjusts the aperture, and the camera will keep the shutter speed such that the exposure is correct. (you change to a smaller aperture and the camera will pick a slower shutter speed)

In Tv mode, you turn that same knob, but now it changes the shutter speed, and the camera automatically adjusts the aperture.

If you are in Tv mode and at f/4 and 1/60th and switch to 1/30th the aperture will change to f/5.6. Change shutter to 1/15th and aperture will change to f/8.

In Av mode, at f/4 and 1/60th, switch to f/5.6 and the shutter will adjust to 1/30. Switch to f/8 and the shutter will go to 1/15th.

If you notice the above, you end up with the same exact combinations.

So there is no difference in the way your pictures will look switching between Av and Tv. They are just a convenient way to tell the camera which of the two settings (shutter speed or aperture) you want to choose yourself, and let the camera choose the other. But a picture at f/4 and 1/60 will look the same whether you're in Av or Tv or Manual or Auto mode. Just a difference in which settings you're picking, and which ones you're leaving to the camera.

If you are in Tv mode in other words, and want shallow depth of field, you can just speed up the shutter to 1/125 or 1/250 and watch the corresponding aperture go wider and wider to f/2.8 or f/1.8 or whatever.

I imagine that's confused you beyond any hope of salvation now :)

January 8th, 2012
@voodoochild bing! tv versus av thought is correct...however remember all the other factors (iso, shutter speed, etc) still play into gettting the shot!
January 8th, 2012
@mikew no, it hasn't made it all murkier. It helped.
January 8th, 2012
@shadesofgrey lol, but of course...as long as I have the ground level understanding of why I have both ie what circumstances determine which setting I've a chance.
January 8th, 2012
@voodoochild go forth and do good work!
January 8th, 2012
@shadesofgrey lol. I will try. I have been wondering about asking for a challenge a month where you get told to go and fiddle with a particular setting as a way of helping those of us less experienced mortals. Guess I got my first challenge :)
January 8th, 2012
I reckon you've got it. Infact I reckon you had it before you started this thread, only you weren't thinking about it in *quite* the right way. There have been a few good explanations above, but if it helps, I'll explain the way I think about it too. The experts might criticise some of what I'm about to say, which is why I stress that this is the way *I* got it straight in my little head!

Both aperture and time are two of factors that can be used to control how much light enters the camera. Av and Tv modes on a camera means you only have to worry about one of these. The camera will adjust the other to give the optimal amount light entry.

So if you start in Av, by setting the aperture to x, the camera will adjust the shutter time to y (for optimal light entry) and give you a photo z. If you then set the camera to Tv and set the shutter time to y, the camera will adjust the aperture (which, if you made a note of it when you were in Av, you'll see it's y again) and give you photo z. So you've obtained two identical photos, using identical settings - one by controlling the time, and the other by controlling the aperture size. This is what you were describing in your original post.

What you need to do when you take any particular shot is to think "what is my PRIORITY" (clue's in the name!) for this shot? Do I want a particular depth of field (use Av) or do I want a particular shutter time (use Tv). Then let the camera sort the other out accordingly.

Examples of all 4 possible extreme examples -

1. Closeup of something e.g. flower where you'd like the background to be blurred - use Av with a low number(large aperture). The camera will most likely choose a fast shutter speed for you.

2. A photo of multiple objects at different distances from the camera where they're ALL in focus - use Av with a high number (small aperture). The camera will choose a slower shutter speed.

3. To "freeze" a moving thing - e.g. your fan, with 3 separate blades showing - use Tv with a fast shutter speed. The camera will most likely choose a large aperture (small number) for you.

4. Movement of a moving thing (e.g. your fan where the blades are blurred, or flowing waterfalls etc) - use Tv with a long shutter speed. The camera will choose a smaller aperture (large number).

I think you've already understood the above from all the other explanations, but if you try and think and memorise 4 examples (one for each of the above scenarios) that you've taken yourself...you'll be able to apply them to all of your future shots (that's how I learnt/understood/remembered!).


The next step would be ISO, and whilst a lot of people find it confusing, I find the easiest way of thinking of the ISO is like changing a gear on your car (if you drive manual!). I'll explain.

If you're shooting in darker conditions e.g. indoors, you might find that if you shoot in Av with the largest possible aperture (small number) in order to get the camera to choose the fastest shutter speed, it may still be too slow, and you'll get a blurred photo (because you'll have moved whilst the shutter is open, or your subject will have!). And if you shoot in Tv with a shutter speed that's fast enough for you to be able to hold still for, you might find the shot is too dark. So what do you do?! You change the ISO.

Increasing the ISO is like changing a gear in a car so that you can change your speed without having your foot down as far on the board! In camera terms, it means you can take a "lighter" picture in darker conditions with a faster shutter speed. Using 100-400 you probably won't notice *much* difference in quality but when you go towards 800+ you may find that the photo's a little grainy (like old fashioned music concert shots). So always shoot with the lowest ISO possible (I keep my camera on 100 unless it needs to be increased). Only move up if the light is too low for you to get a decent photo at a sensible shutter speed (so that there's no camera shake).

Alternatively, in poor light conditions, you'll be able to maintain a lower ISO (and sharper/crisper better quality photo) if you use a tripod (to keep the camera still for shots that need a long exposure).

I hope that (might) have been of some help! Like I said, I'm no expert - I've just explained how *I* see and remember it! The best way is to try and shoot as many of each of the above 4 examples as possible, just to get a feel for things. Do it in well lit conditions to start with though so that you don't have to mess around with ISO. Then when you've got it straight in your head, move to a less well lit room, and try again, experimenting with changing the ISO! To be honest, when you've got that, you'll be more or less ready to shoot in full manual :D

Good luck!
January 8th, 2012
@voodoochild I could be wrong but I have always thought of AV and TV as two different ways to control the image I want.

I shoot mainly in AV mode - aperture priority because I like to control that element the most. When I shoot in AV I choose the aperture = amount of light and the depth of the field (how much is in focus) and the camera works out which shutter speed will balance my shot for the correct exposure.

Occasionally I will shoot in TV mode which allows me to control the shutter speed - how long the shutter is open and therefore the amount of light that come is. I usually only play with this if I want a long exposure for night shot or to achieve the "blur" of motion - ie waterfalls etc. The camera in this case will choose the correct aperture to expose the picture ... but often I don't like the aperture it chooses so I move into full manual

... does that help at all
January 8th, 2012
@voodoochild
Can't believe nobody actually picked you up on calling you dense. Can I call it you just for the record? dense.
Have you resolved your issue?

Don't stop at TV or AV, they're there to confuse you. Go straight to 'M' the king of settings. Then picture the sliding scale things on Windows picture viewer - you know contrast, brightness, saturation scales. you've got four inside your camera that you are going to slide either way to make the picture perfect. Its as simple as that.
1. ISO 100 needs a lot of light, 1600 doesn't - adjust inbetween.
2. Focus, take AF off and use manual focus, twist the focus ring till it's crisp
3. Shutter speed, fast shutter makes it crystal, slow shutter blurred
4. F stop - 1.8/2/2.8 crisp foreground, 11-18-22 crisp everything

A guide to photography summed up by an idiot (me) slide the scales until you're happy - BUT and here's where it gets technical - compensate one for the other when you want a specific effect. So you want blur (erm why?) slow down your speed but you'll have to go for a high number f stop else it will be overexposed. This is how I think of it and it works for me. Never shoot automatic - this is my advice for everyone, else you could have saved $500 and bought a compact. Good luck.
January 8th, 2012
AV is there because you can buy lenses for your camera which are not just cheap hunks of plastic. When you get an OM zuiko lens or a nice Zeiss lens fitted to your DSLR you put the camera to AV and slide the focus ring on the lens and your camera adjusts, still it isn't as good as M because you're losing the shutterspeed slider and losing control therefore of the system. M is king.
January 8th, 2012
@chewyteeth feel free to call me dense :P
Just a question, you might not know the answer but if I don't ask, I'll never know.I was thinking about this a little while ago when fretting about remembering which f stop to use - I use to have an SLR. Film and all. I got decent photos....and there was no auto scene setting so I must have been doing all this stuff surely? For focus- I just twisted the focus ring till it was crisp. Light meter- little button to press and then alter something till the line was in the middle ...........
Have I just been making things harder for myself trying to figure out AV etc lol?

Tomorrow I fully intend on dragging my old SLR out and looking at it properly and seeing what I used to do with it. (it's 24 years and 4 kids since I used it, I hope I can be forgiven for not remembering.)
January 8th, 2012
Kudos to you for taking the next step. Now, don't go back to auto. You've gone through all this to learn the camera, keep learning it. It will get easier as you get more used to how it works. It's not as complex as people think. It's like learning to use a new Facebook design. it is different and takes some time to understand it but eventually it all just becomes natural and comfortable. I hope others follow your lead. :-)
January 8th, 2012
@voodoochild
Yep, think film SLR. When I shoot with my fancy film SLR I do set it to AV, I fix it on a low number because I like a shallow depth of field usually, then I let the camera do half the work with deciding the shutter speed for the light. So weirdly, on a film camera I use that setting. On a digital though, because I know exactly whats happening, there's no mystery to how the pics come out, I do total manual. I start each new situation by roughly judging f 2.8, 250, or 1000, or 50th and I take a pic, then I work out where I need to go from there. My lenses are all Pentax lenses on my Canon EOS body so they're all ring-adjusting f.stop like on a film SLR - so I don't have the option for automatic. This is how I like to shoot and it gives me maximum control. Find whats good for you, but I would say - try manual - M - and if you're struggling go back to the other inbetween options - I don't even know what TV means, I've never used it but on the Canon when you select an option the screen tells you what it is. What film SLR do you have? You should get a ring adaptor and start using film lenses on your digi if you're ready to shoot manual. Save hundreds! x
January 8th, 2012
Looks like you got a lot of help here (I didn't read thru all the responses) but the best thing my husband and I ever did was take a series of classes at the local college and we are signed up for some at a local photography equipment store.
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