Exposure question

Culture · 09-13-2011, 01:46 AM

Originally posted by Just1MoreDave

I stay in Aperture Priority mode even when I shouldn't. Sometimes I realize I am working too hard, trying to control shutter speed by figuring out in my head how many stops to change the aperture to get a particular shutter speed. Then I remember the camera has a mode that does it for me.

The mode you use should be something you are completely comfortable in, and allow you to quickly access the things you want the most control over. All modes can be forced to come up with the same exposure values, with more or less work. But if you want to change something for your next shot, you want a mode that avoids fumbling or taking your eye from the viewfinder. So think about what setting you want to control, what setting won't affect the photo a lot, what would work OK on Auto, and then choose a mode for that. You should check the manual or take a few shots to confirm how your new mode works. Comfort will come with practice.

Auto ISO works a little differently with each camera generation. The upper-tier models like the K-7 allow you to influence when it decides to raise ISO.

[Edit] OK, I figured out you have the K-m. You have the option to set the range of ISOs the camera can use, p. 87 in your manual. You can set the camera to use full or half-stops when it's choosing an ISO (p. 78). Your camera won't do Auto ISO in Manual Mode. Scene modes will use their own logic for ISO and Bulb mode will make it drop to the lowest possible value. The other choices it makes are kind of obscure and you can't control them. One thing it will do is try to follow the rule for keeping shutter speed in the handheld range. So if you're in Av, Auto ISO with the kit lens at 30mm and choose an aperture that would drop shutter speed, the camera will bump ISO to keep the shuttter speed in handheld range. A lot of people complain that with a flash, Auto ISO goes to the maximum ISO. I'm not sure what the K-m does here.

Thanks Dave,
That is is exactly what I have observed with the
ISO setting. I have tried to move the camera from good light to low light to see how the ISO range responds in connection with the shutter speed. I have found out that at times in low light, the it does not move to the maximum setting on the range. I wouldnt mind if the shutter speed was ok. But at times the shutter speed is low and yet still the range is not in the maximum on the ISO range setting.

Culture · 09-13-2011, 01:56 AM

Originally posted by RioRico

Hardly any time at all! In M mode, punching the Green button is fast. In an Auto mode, punching the AE-L button is fast. I mean like one second. Setting bracketing takes a little longer, like 3-5 seconds -- and on my K20D in RAW, there's a 3-second write delay after shooting. Chimping is slightly slower but requires more brainpower, which I sometimes lack. Duh...

Spray and pray!

Back in the day, my main camera for awhile was an ancient folder, a German 1934 Kodak Retina 1, the very first 135 camera. With a great 50/3.5 lens, manual shutter, no rangefinder, no metering, no nothing but focus-shutter-aperture controls. After a couple intensive months, it became totally instinctive. Look at a scene, judge the distance and light -- then my fingers automatically made the adjustments, and I shot. And turned the film knob; no quick-advance lever either! A light-meter in my pocket, just in case, but otherwise it's all a matter of experience. Look, diddle, shoot, nice and easy!

My point is: don't panic. Learn to judge scenes. For exposure, remember that you're not capturing subjects, you're capturing LIGHT -- so learn to judge light and shadow. With an AF lens and the camera in P mode and center-weighted metering, you should be able to look at a subject and judge whether you need to tweak the EV compensation. Then shoot and chimp and adjust and shoot again. And if you're in a hurry and get the exposure wrong, well, it can be fixed in PP.

And that is one more problem that I looking to overcome someday. I really dont like post processing. I basically dont have the time. I could be lazy but I am not sure.
For instance when I take 50 "good" pictures, how many of them do I actually have to pp. Any ideas?

RioRico · 09-13-2011, 02:25 AM

Originally posted by Culture

And that is one more problem that I looking to overcome someday. I really dont like post processing. I basically dont have the time.

Then bracket. But for me, PP is part of the picture-making process. In my profile, I list among my interests: "to capture and torture sounds and images". Torturing them is the fun part!

Quote:

For instance when I take 50 "good" pictures, how many of them do I actually have to pp. Any ideas?

It depends on what you want your images to look like, whether you want to take pictures or make pictures, stuff like that. I PP everything, and have since I started electronic imaging 15 years ago. And before that was darkroom work, which is also PP (and much smellier than digital editing). An image isn't mine until I've pissed on it like a dog marking territory.

Culture · 09-13-2011, 03:04 AM

Originally posted by RioRico

Then bracket. But for me, PP is part of the picture-making process. In my profile, I list among my interests: "to capture and torture sounds and images". Torturing them is the fun part!

It depends on what you want your images to look like, whether you want to take pictures or make pictures, stuff like that. I PP everything, and have since I started electronic imaging 15 years ago. And before that was darkroom work, which is also PP (and much smellier than digital editing). An image isn't mine until I've pissed on it like a dog marking territory.

SpeedyTortoise · 09-13-2011, 06:29 AM

Originally posted by Culture

Yeah I understand what you guys are saying. and basically that is the way I shoot. I do shoot mainly in Av mode. The problem that my mind cant seem to comprehend is that if say your f-stop is 2.0 and shutter speed is 1/90. Under the same condition and exposure shouldnt you get the same values whether in Av or Tv mode.

Am I wrong to think this?

Culture, perhaps this will help:

In Av mode, you set the aperture, and the camera adjusts the shutter speed to get the correct exposure.
In Tv mode, you set the shutter speed, and the camera adjusts the aperture to get the correct exposure.

Here is an example of why you might choose one mode over another:

Say you were shooting a basketball game, and you were trying to capture someone running. If you shoot in Av mode, with the aperture (f-stop) at 3.5, the camera may set the shutter speed to, say 1/60 to allow enough light in to the camera to get the shot correctly exposed. The problem is that your picture will then be really blurry, because the player moves a lot in 1/60 of a second. But if you switch to Tv (shutter priority) mode, you could set the shutter speed to 1/500 sec to make sure the action is frozen, and then let the camera adjust the aperture to as open as it can be, and the ISO will go up if you have the ISO on auto.

In other words, while the camera will attempt to find a correct exposure for you under either setting, there are multiple combinations of options to get a correct exposure. By using one mode or the other, you prioritize which setting must stay consistent. Shutter priority is good if you are capturing movement.

On the other hand, Av mode is useful if you want to get precise depth of field settings. For example, say you are taking a picture of a flower on a sunny day. In auto mode, the camera will probably default to a high f-stop value like f/5.6 or higher, because it is very bright, and too much light will let the camera in. But if you want to get that cool effect where the background is blurry and the flower is in sharp focus, you would want to switch to Av mode to put the aperture as open as possible (say f/2.0). Then the camera will automatically make the shutter speed really fast to compensate for the open aperture, to get a correct exposure.

You could get the same flower picture with a correct exposure in Tv mode, but depending on what you set the shutter speed too, you wouldn't get the same effect.

That was longer than I intended it to be. Hope it helps!

wsteffey · 09-13-2011, 06:56 AM

The best advice on which settings to use under any given condition will come from your camera. Turn your camera on, set it on automatic and push the shutter release 1/2 way. The display will show the best compromise settings for ISO, shutter speed, and lens. While you are there, take the shot. Even if it isn't perfect it will give you a base-line for later comparisons. Today's cameras are programmed to try and reach a "sweet-spot", where all three components will probably produce a good photograph. Outdoors in daylight for example: ISO 200, shutter 1/125, lens 8.0. All of these recommendations are "average", compatible with the others, and good only for the instant your press the shutter release. Why ISO 200?. Depending on the camera, higher might add noise to the photograph, lower might require less than optimum shutter speed or lens setting. A shutter speed of 1/125 is fast enough to stop most action, but slow enough to let in enough light. Very few lenses give sharp, distortion free results wide open, most start to reach maximum sharpness at 5.6-8.0.

Keep in mind that if you manually adjust any one of these parameters you will have to adjust at least one of the others to compensate. For example, if you increase your shutter speed to 1/250 to stop faster action you will have to either raise the ISO, or open up the lens to let in more light. Or, if you close down the lens to 11.0 for greater depth of field you will have to decrease the shutter speed to let in more light. All three components have an optimum range of settings. For example, my K100 works best with an ISO of 200-400. My Sigma APO/DG 70-300 best between f8 and f11. With the Sigma, hand held slower than 1/125-1/250 is optimum. Let anything get outside these ranges and the photograph will degrade. My Pentax 50-200, or the 18-55 kit lens have different envelopes.

Confusing? Yes, at the beginning, but that is why all Pentax cameras have an automatic, P (think automatic with benefits) and scene settings. Nothing about your final photograph will scream (I used "automatic" because I am a beginner. It is the result that counts. Also, many manual setting users are taking landscapes or other static objects. You might want to use automation for active subjects, kids, horses, sports etc., and practice manual settings on subjects that don't move.

Culture · 09-13-2011, 09:09 AM

Ok let me put it simple since others seem to be getting the wrong idea about my question
Under the same condition and light meaning exposure.
Av mode: f-stop 2.0, shutter speed 1/120
Tv mode: shutter speed 120, f-stop 2.0
Does that mean the flower will look the same with a nice bokeh?
If it will look the same will you still prefer a particular mode?

newarts · 09-13-2011, 09:50 AM

Originally posted by Culture

Ok let me put it simple since others seem to be getting the wrong idea about my question
Under the same condition and light meaning exposure.
Av mode: f-stop 2.0, shutter speed 1/120
Tv mode: shutter speed 120, f-stop 2.0
Does that mean the flower will look the same ......?
If it will look the same will you still prefer a particular mode?

Yes both will look the same since both f-stop and speed are the same - that is the two modes are giving the same speed and fstop. There is no reason to choose one mode over another if speed & dof will be the same.

But if you had set
Av to f:1.4 then speed would automatically be 1/240 shallower dof & less sensitivity to motion
or
Tv to 1/60 then f-stop would automatically be f:2.8 deeper dof & more sensitivity to motion

The exposures would be equivalent but the results different.

One way to avoid such decisions is to use the camera's scene modes.

RioRico · 09-13-2011, 10:48 AM

As newarts said, pictures taken with the same aperture and shutter (with everything else [ISO, light, angle, distance, etc] being equal) will look the same, no matter which modes got you there. And pictures taken with the same EV (combined effect of ISO, aperture and shutter) will be exposed the same but will have different DOF and motion blurring -- again, the modes that got you there don't matter to the captured image.

The shooting modes are just various paths to the same end. They're like descending in a tall building; you can take escalator, elevator, stairs, slide down a pole or rope, use rock-climbing techniques or a spiderman-web, or just jump out a window (with or without a parachute). They all take you to the same place.

P mode is a gateway combining Av and Tv modes. Try this: In P mode, aim at something. Take a meter reading by half-pressing and releasing the shutter button. Now spin the eDial to change the settings. Look through the viewfinder, or at the top LCD screen; note that shutter speed and aperture change in tandem to stay at the same EV. The light captured remains the same at all those settings, but the images will have different sharpness/blur, DOF, bokeh, all that stuff. You're invisibly changing modes.

EACH OF THOSE SETTINGS IS A DIFFERENT SOLUTION TO THE PROBLEM OF GRABBING THE IMAGE. Every shot is a problem to be solved; that's the fun here!
_____________________________________________________________

EDIT/addendum: Earlier I mentioned using M mode in consistent light even with AF lenses. Here is an example.

I was in the Red Rock country around Sedona Arizona, shooting under clean blue skies with white puffy clouds. The 'scape was red rocks, tawny sand, plants of various shades of green, adobe and wood buildings, that sort of stuff. If I had been in an auto mode, every slight shift of angle would result in a different exposure. So I did some quick test metering and shooting and chimping until I found the setting that provided the best results, the truest colors. I left it at that setting for 2-3 hours of shooting 'scapes with the same zoom. Consistent light + consistent setting = consistent results.

And I could have done that without even metering, by using the SUNNY 16 RULE. Remember my spiel about the ancient Kodak Retina 1 folder, back in post#16? That's a technique I used with it. No chimping allowed then! And yet it worked pretty damn well.

See also WHY YOUR LIGHT METER LIES TO YOU.

SpeedyTortoise · 09-13-2011, 11:15 AM

Originally posted by Culture

Ok let me put it simple since others seem to be getting the wrong idea about my question
Under the same condition and light meaning exposure.
Av mode: f-stop 2.0, shutter speed 1/120
Tv mode: shutter speed 120, f-stop 2.0
Does that mean the flower will look the same with a nice bokeh?
If it will look the same will you still prefer a particular mode?

Yes, if the settings are the same, you'll get the same effect, as newarts/Rio said.

However, yes, I would still prefer a particular mode, because camera's settings can change based on a number of things: For example, if the sun peeks out from the clouds, or I change camera position: if I'm shooting in Av, I'll still retain my 2.0 aperture. But if I was shooting in Tv, then the camera might adjust my aperture, ruining my bokeh effect.

I hope that makes sense.

RioRico · 09-13-2011, 11:55 AM

Originally posted by SpeedyTortoise

I would still prefer a particular mode, because camera's settings can change based on a number of things: For example, if the sun peeks out from the clouds, or I change camera position: if I'm shooting in Av, I'll still retain my 2.0 aperture. But if I was shooting in Tv, then the camera might adjust my aperture, ruining my bokeh effect.

Quite right. Selecting any particular mode lets us control the DOF, bokeh, motion-capture, etc. necessary for particular shots and effects. (And of course non-A-type manual lenses force us into Av or M modes.) Those of us with cameras with TAv mode (like my K20D) have even more control over the automation: select a speed and aperture and let the ISO float to whatever level is needed for the exposure. All good tools!

bimjo · 09-13-2011, 01:41 PM

At the risk of having missed this as I skimmed the posts, let's keep it simple:

If you want to control the DOF you shoot Av mode and pick your aperture.
If you want to control the motion of your subject (freeze or blur it) shoot Tv mode and pick your shutter speed.
Hypermodes blur the lines a bit, but that's basically it.

And yes, if both aperture and shutter speed values happened to be the same in both modes, you'd get the same pic.

RioRico · 09-13-2011, 02:34 PM

Originally posted by bimjo

If you want to control the DOF you shoot Av mode and pick your aperture.
If you want to control the motion of your subject (freeze or blur it) shoot Tv mode and pick your shutter speed.
Hypermodes blur the lines a bit, but that's basically it.

And if you want to control noise, you shoot Sv mode or otherwise set the ISO.

**Just1MoreDave** · 09-13-2011, 02:52 PM

Originally posted by bimjo

...Hypermodes blur the lines a bit, but that's basically it.

With a full set of KA-mount lenses (i.e., the aperture can be set by the camera) and a camera with 2 control wheels, P mode is all you really need, because it can instantly switch to other modes.

Culture · 09-13-2011, 09:13 PM

Thanks guys for all the answers. I think one thing that I have learnt and deduce from this tread is that as far as f-stop is not blinking, and shutter speed is not blinking is that exposure is always the same.
I dont know why i have not thought of it like that.

So I guess my next question is how often do you shoot with f-stop or shutter speed blinking?

09-13-2011, 06:56 AM	#21
wsteffey Senior Member Join Date: May 2010 Photos: Gallery \| Albums Posts: 106	Which settings to use The best advice on which settings to use under any given condition will come from your camera. Turn your camera on, set it on automatic and push the shutter release 1/2 way. The display will show the best compromise settings for ISO, shutter speed, and lens. While you are there, take the shot. Even if it isn't perfect it will give you a base-line for later comparisons. Today's cameras are programmed to try and reach a "sweet-spot", where all three components will probably produce a good photograph. Outdoors in daylight for example: ISO 200, shutter 1/125, lens 8.0. All of these recommendations are "average", compatible with the others, and good only for the instant your press the shutter release. Why ISO 200?. Depending on the camera, higher might add noise to the photograph, lower might require less than optimum shutter speed or lens setting. A shutter speed of 1/125 is fast enough to stop most action, but slow enough to let in enough light. Very few lenses give sharp, distortion free results wide open, most start to reach maximum sharpness at 5.6-8.0. Keep in mind that if you manually adjust any one of these parameters you will have to adjust at least one of the others to compensate. For example, if you increase your shutter speed to 1/250 to stop faster action you will have to either raise the ISO, or open up the lens to let in more light. Or, if you close down the lens to 11.0 for greater depth of field you will have to decrease the shutter speed to let in more light. All three components have an optimum range of settings. For example, my K100 works best with an ISO of 200-400. My Sigma APO/DG 70-300 best between f8 and f11. With the Sigma, hand held slower than 1/125-1/250 is optimum. Let anything get outside these ranges and the photograph will degrade. My Pentax 50-200, or the 18-55 kit lens have different envelopes. Confusing? Yes, at the beginning, but that is why all Pentax cameras have an automatic, P (think automatic with benefits) and scene settings. Nothing about your final photograph will scream (I used "automatic" because I am a beginner. It is the result that counts. Also, many manual setting users are taking landscapes or other static objects. You might want to use automation for active subjects, kids, horses, sports etc., and practice manual settings on subjects that don't move.

09-13-2011, 10:48 AM	#24
RioRico Veteran Member Join Date: Jun 2008 Location: Limbo, California Posts: 11,263	As newarts said, pictures taken with the same aperture and shutter (with everything else [ISO, light, angle, distance, etc] being equal) will look the same, no matter which modes got you there. And pictures taken with the same EV (combined effect of ISO, aperture and shutter) will be exposed the same but will have different DOF and motion blurring -- again, the modes that got you there don't matter to the captured image. The shooting modes are just various paths to the same end. They're like descending in a tall building; you can take escalator, elevator, stairs, slide down a pole or rope, use rock-climbing techniques or a spiderman-web, or just jump out a window (with or without a parachute). They all take you to the same place. P mode is a gateway combining Av and Tv modes. Try this: In P mode, aim at something. Take a meter reading by half-pressing and releasing the shutter button. Now spin the eDial to change the settings. Look through the viewfinder, or at the top LCD screen; note that shutter speed and aperture change in tandem to stay at the same EV. The light captured remains the same at all those settings, but the images will have different sharpness/blur, DOF, bokeh, all that stuff. You're invisibly changing modes. EACH OF THOSE SETTINGS IS A DIFFERENT SOLUTION TO THE PROBLEM OF GRABBING THE IMAGE. Every shot is a problem to be solved; that's the fun here! _____________________________________________________________ EDIT/addendum: Earlier I mentioned using M mode in consistent light even with AF lenses. Here is an example. I was in the Red Rock country around Sedona Arizona, shooting under clean blue skies with white puffy clouds. The 'scape was red rocks, tawny sand, plants of various shades of green, adobe and wood buildings, that sort of stuff. If I had been in an auto mode, every slight shift of angle would result in a different exposure. So I did some quick test metering and shooting and chimping until I found the setting that provided the best results, the truest colors. I left it at that setting for 2-3 hours of shooting 'scapes with the same zoom. Consistent light + consistent setting = consistent results. And I could have done that without even metering, by using the SUNNY 16 RULE. Remember my spiel about the ancient Kodak Retina 1 folder, back in post#16? That's a technique I used with it. No chimping allowed then! And yet it worked pretty damn well. See also WHY YOUR LIGHT METER LIES TO YOU. Last edited by RioRico; 09-13-2011 at 12:38 PM. Reason: addendum

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09-13-2011, 01:46 AM	#16
Culture Veteran Member Join Date: Sep 2011 Location: Vaasa Photos: Gallery \| Albums Posts: 818 Original Poster	Originally posted by Just1MoreDave I stay in Aperture Priority mode even when I shouldn't. Sometimes I realize I am working too hard, trying to control shutter speed by figuring out in my head how many stops to change the aperture to get a particular shutter speed. Then I remember the camera has a mode that does it for me. The mode you use should be something you are completely comfortable in, and allow you to quickly access the things you want the most control over. All modes can be forced to come up with the same exposure values, with more or less work. But if you want to change something for your next shot, you want a mode that avoids fumbling or taking your eye from the viewfinder. So think about what setting you want to control, what setting won't affect the photo a lot, what would work OK on Auto, and then choose a mode for that. You should check the manual or take a few shots to confirm how your new mode works. Comfort will come with practice. Auto ISO works a little differently with each camera generation. The upper-tier models like the K-7 allow you to influence when it decides to raise ISO. [Edit] OK, I figured out you have the K-m. You have the option to set the range of ISOs the camera can use, p. 87 in your manual. You can set the camera to use full or half-stops when it's choosing an ISO (p. 78). Your camera won't do Auto ISO in Manual Mode. Scene modes will use their own logic for ISO and Bulb mode will make it drop to the lowest possible value. The other choices it makes are kind of obscure and you can't control them. One thing it will do is try to follow the rule for keeping shutter speed in the handheld range. So if you're in Av, Auto ISO with the kit lens at 30mm and choose an aperture that would drop shutter speed, the camera will bump ISO to keep the shuttter speed in handheld range. A lot of people complain that with a flash, Auto ISO goes to the maximum ISO. I'm not sure what the K-m does here. Thanks Dave, That is is exactly what I have observed with the ISO setting. I have tried to move the camera from good light to low light to see how the ISO range responds in connection with the shutter speed. I have found out that at times in low light, the it does not move to the maximum setting on the range. I wouldnt mind if the shutter speed was ok. But at times the shutter speed is low and yet still the range is not in the maximum on the ISO range setting.

09-13-2011, 01:56 AM	#17
Culture Veteran Member Join Date: Sep 2011 Location: Vaasa Photos: Gallery \| Albums Posts: 818 Original Poster	Originally posted by RioRico Hardly any time at all! In M mode, punching the Green button is fast. In an Auto mode, punching the AE-L button is fast. I mean like one second. Setting bracketing takes a little longer, like 3-5 seconds -- and on my K20D in RAW, there's a 3-second write delay after shooting. Chimping is slightly slower but requires more brainpower, which I sometimes lack. Duh... Spray and pray! Back in the day, my main camera for awhile was an ancient folder, a German 1934 Kodak Retina 1, the very first 135 camera. With a great 50/3.5 lens, manual shutter, no rangefinder, no metering, no nothing but focus-shutter-aperture controls. After a couple intensive months, it became totally instinctive. Look at a scene, judge the distance and light -- then my fingers automatically made the adjustments, and I shot. And turned the film knob; no quick-advance lever either! A light-meter in my pocket, just in case, but otherwise it's all a matter of experience. Look, diddle, shoot, nice and easy! My point is: don't panic. Learn to judge scenes. For exposure, remember that you're not capturing subjects, you're capturing LIGHT -- so learn to judge light and shadow. With an AF lens and the camera in P mode and center-weighted metering, you should be able to look at a subject and judge whether you need to tweak the EV compensation. Then shoot and chimp and adjust and shoot again. And if you're in a hurry and get the exposure wrong, well, it can be fixed in PP. And that is one more problem that I looking to overcome someday. I really dont like post processing. I basically dont have the time. I could be lazy but I am not sure. For instance when I take 50 "good" pictures, how many of them do I actually have to pp. Any ideas?

09-13-2011, 02:25 AM	#18
RioRico Veteran Member Join Date: Jun 2008 Location: Limbo, California Posts: 11,263	Originally posted by Culture And that is one more problem that I looking to overcome someday. I really dont like post processing. I basically dont have the time. Then bracket. But for me, PP is part of the picture-making process. In my profile, I list among my interests: "to capture and torture sounds and images". Torturing them is the fun part! Quote: For instance when I take 50 "good" pictures, how many of them do I actually have to pp. Any ideas? It depends on what you want your images to look like, whether you want to take pictures or make pictures, stuff like that. I PP everything, and have since I started electronic imaging 15 years ago. And before that was darkroom work, which is also PP (and much smellier than digital editing). An image isn't mine until I've pissed on it like a dog marking territory.

09-13-2011, 03:04 AM	#19
Culture Veteran Member Join Date: Sep 2011 Location: Vaasa Photos: Gallery \| Albums Posts: 818 Original Poster	Originally posted by RioRico Then bracket. But for me, PP is part of the picture-making process. In my profile, I list among my interests: "to capture and torture sounds and images". Torturing them is the fun part! It depends on what you want your images to look like, whether you want to take pictures or make pictures, stuff like that. I PP everything, and have since I started electronic imaging 15 years ago. And before that was darkroom work, which is also PP (and much smellier than digital editing). An image isn't mine until I've pissed on it like a dog marking territory.

09-13-2011, 06:29 AM	#20
SpeedyTortoise New Member Join Date: Sep 2011 Location: Oklahoma Posts: 4	Originally posted by Culture Yeah I understand what you guys are saying. and basically that is the way I shoot. I do shoot mainly in Av mode. The problem that my mind cant seem to comprehend is that if say your f-stop is 2.0 and shutter speed is 1/90. Under the same condition and exposure shouldnt you get the same values whether in Av or Tv mode. Am I wrong to think this? Culture, perhaps this will help: In Av mode, you set the aperture, and the camera adjusts the shutter speed to get the correct exposure. In Tv mode, you set the shutter speed, and the camera adjusts the aperture to get the correct exposure. Here is an example of why you might choose one mode over another: Say you were shooting a basketball game, and you were trying to capture someone running. If you shoot in Av mode, with the aperture (f-stop) at 3.5, the camera may set the shutter speed to, say 1/60 to allow enough light in to the camera to get the shot correctly exposed. The problem is that your picture will then be really blurry, because the player moves a lot in 1/60 of a second. But if you switch to Tv (shutter priority) mode, you could set the shutter speed to 1/500 sec to make sure the action is frozen, and then let the camera adjust the aperture to as open as it can be, and the ISO will go up if you have the ISO on auto. In other words, while the camera will attempt to find a correct exposure for you under either setting, there are multiple combinations of options to get a correct exposure. By using one mode or the other, you prioritize which setting must stay consistent. Shutter priority is good if you are capturing movement. On the other hand, Av mode is useful if you want to get precise depth of field settings. For example, say you are taking a picture of a flower on a sunny day. In auto mode, the camera will probably default to a high f-stop value like f/5.6 or higher, because it is very bright, and too much light will let the camera in. But if you want to get that cool effect where the background is blurry and the flower is in sharp focus, you would want to switch to Av mode to put the aperture as open as possible (say f/2.0). Then the camera will automatically make the shutter speed really fast to compensate for the open aperture, to get a correct exposure. You could get the same flower picture with a correct exposure in Tv mode, but depending on what you set the shutter speed too, you wouldn't get the same effect. That was longer than I intended it to be. Hope it helps!

09-13-2011, 09:09 AM	#22
Culture Veteran Member Join Date: Sep 2011 Location: Vaasa Photos: Gallery \| Albums Posts: 818 Original Poster	Ok let me put it simple since others seem to be getting the wrong idea about my question Under the same condition and light meaning exposure. Av mode: f-stop 2.0, shutter speed 1/120 Tv mode: shutter speed 120, f-stop 2.0 Does that mean the flower will look the same with a nice bokeh? If it will look the same will you still prefer a particular mode?

09-13-2011, 09:50 AM	#23
newarts Inactive Account Join Date: Dec 2008 Location: Ames, Iowa, USA Photos: Albums Posts: 2,965	Originally posted by Culture Ok let me put it simple since others seem to be getting the wrong idea about my question Under the same condition and light meaning exposure. Av mode: f-stop 2.0, shutter speed 1/120 Tv mode: shutter speed 120, f-stop 2.0 Does that mean the flower will look the same ......? If it will look the same will you still prefer a particular mode? Yes both will look the same since both f-stop and speed are the same - that is the two modes are giving the same speed and fstop. There is no reason to choose one mode over another if speed & dof will be the same. But if you had set Av to f:1.4 then speed would automatically be 1/240 shallower dof & less sensitivity to motion or Tv to 1/60 then f-stop would automatically be f:2.8 deeper dof & more sensitivity to motion The exposures would be equivalent but the results different. One way to avoid such decisions is to use the camera's scene modes.

09-13-2011, 11:15 AM	#25
SpeedyTortoise New Member Join Date: Sep 2011 Location: Oklahoma Posts: 4	Originally posted by Culture Ok let me put it simple since others seem to be getting the wrong idea about my question Under the same condition and light meaning exposure. Av mode: f-stop 2.0, shutter speed 1/120 Tv mode: shutter speed 120, f-stop 2.0 Does that mean the flower will look the same with a nice bokeh? If it will look the same will you still prefer a particular mode? Yes, if the settings are the same, you'll get the same effect, as newarts/Rio said. However, yes, I would still prefer a particular mode, because camera's settings can change based on a number of things: For example, if the sun peeks out from the clouds, or I change camera position: if I'm shooting in Av, I'll still retain my 2.0 aperture. But if I was shooting in Tv, then the camera might adjust my aperture, ruining my bokeh effect. I hope that makes sense.

09-13-2011, 11:55 AM	#26
RioRico Veteran Member Join Date: Jun 2008 Location: Limbo, California Posts: 11,263	Originally posted by SpeedyTortoise I would still prefer a particular mode, because camera's settings can change based on a number of things: For example, if the sun peeks out from the clouds, or I change camera position: if I'm shooting in Av, I'll still retain my 2.0 aperture. But if I was shooting in Tv, then the camera might adjust my aperture, ruining my bokeh effect. Quite right. Selecting any particular mode lets us control the DOF, bokeh, motion-capture, etc. necessary for particular shots and effects. (And of course non-A-type manual lenses force us into Av or M modes.) Those of us with cameras with TAv mode (like my K20D) have even more control over the automation: select a speed and aperture and let the ISO float to whatever level is needed for the exposure. All good tools!

09-13-2011, 01:41 PM	#27
bimjo Veteran Member Join Date: Jan 2008 Location: Pasco, WA Posts: 967	At the risk of having missed this as I skimmed the posts, let's keep it simple: If you want to control the DOF you shoot Av mode and pick your aperture. If you want to control the motion of your subject (freeze or blur it) shoot Tv mode and pick your shutter speed. Hypermodes blur the lines a bit, but that's basically it. And yes, if both aperture and shutter speed values happened to be the same in both modes, you'd get the same pic.

09-13-2011, 02:34 PM	#28
RioRico Veteran Member Join Date: Jun 2008 Location: Limbo, California Posts: 11,263	Originally posted by bimjo If you want to control the DOF you shoot Av mode and pick your aperture. If you want to control the motion of your subject (freeze or blur it) shoot Tv mode and pick your shutter speed. Hypermodes blur the lines a bit, but that's basically it. And if you want to control noise, you shoot Sv mode or otherwise set the ISO.

09-13-2011, 02:52 PM	#29
Just1MoreDave Site Supporter Join Date: Feb 2007 Location: Aurora, CO Photos: Gallery \| Albums Posts: 6,340	Originally posted by bimjo ...Hypermodes blur the lines a bit, but that's basically it. With a full set of KA-mount lenses (i.e., the aperture can be set by the camera) and a camera with 2 control wheels, P mode is all you really need, because it can instantly switch to other modes.

09-13-2011, 09:13 PM	#30
Culture Veteran Member Join Date: Sep 2011 Location: Vaasa Photos: Gallery \| Albums Posts: 818 Original Poster	Thanks guys for all the answers. I think one thing that I have learnt and deduce from this tread is that as far as f-stop is not blinking, and shutter speed is not blinking is that exposure is always the same. I dont know why i have not thought of it like that. So I guess my next question is how often do you shoot with f-stop or shutter speed blinking?