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Thread started 27 Jun 2010 (Sunday) 02:02
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Issues with my 40D...

 
TheBurningCrown
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Jun 28, 2010 01:44 as a reply to  @ post 10438573 |  #31

bananas13 wrote in post #10438510 (external link)
W...and I think it's a little irrelevant to the topic to judge my lack of photography knowledge.

Quite honestly I think it's your lack of photography knowledge which started this topic in the first place.

Trust that your gear works just fine and concentrate on learning more about photography itself - we all have to start somewhere.


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bananas13
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Jun 28, 2010 02:14 |  #32

TheBurningCrown wrote in post #10438645 (external link)
Quite honestly I think it's your lack of photography knowledge which started this topic in the first place.

I know. I tried to edit the title and it didn't work. I just don't understand why it's unusual that I'm a newbie & a photography major... like you said, we all start somewhere.

Perhaps it wasn't meant to be a derogatory statement, but that's how it came across to me.

Whatev. Thanks everyone!


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TheBurningCrown
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Jun 28, 2010 02:43 |  #33

bananas13 wrote in post #10438699 (external link)
I just don't understand why it's unusual that I'm a newbie & a photography major... like you said, we all start somewhere.

Probably because most people don't declare their major until they're somewhat invested in it :p.


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kcbrown
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Jun 28, 2010 03:05 |  #34

bananas13 wrote in post #10438573 (external link)
You have no idea how much that helps me =).

You asked about where I am in my curriculum, I have taken only one class so far (a film based intro class). I got a Rebel in October 2008 while I was majoring in something else. I loved the quality I got out of a DSLR and I found myself wanting to learn more and more... I decided this last year to change my major to photography. So yes, I am new to a lot of this and I can't wait to take more classes this Fall semester!

Ah, okay. That does explain some. I'm a little surprised they didn't cover some of this in a bit more detail in your intro class. Or perhaps they did and it wasn't until later that you discovered how cool this stuff is, at which time you started paying more attention. :)

I really appreciate your reply... the things I've already figured out are:

- Lower f-stop = wider aperture = lower depth of field = faster shutter (and vise-versa)
- Higher ISO = faster shutter = more image noise / Lower ISO = slower shutter = less noise

I know it's not much, but it's a start right?

It's definitely a start. You can go a long way just by understanding the basics. However, please note that it's also a little imprecise. Allow me to add a bit of precision, if I may...

  • Lower f-stop = wider aperture -> shallower depth of field and more light coming in.
  • Higher ISO = more sensitive sensor -> lower overall exposure required to yield same tonal values -> faster shutter and/or narrower aperture to retain same tonality. Also means more noise.
  • Faster shutter = less time for light to come in -> smaller interval of time captured -> stopping motion. Also means less total light coming in.



The basic characteristics of a shot result from a combination of three things: shutter speed, aperture, and ISO. Each of those things has a separate set of implications for your shot.

Shutter speed controls how much time is captured. The longer its open, the more motion blur you'll see. Leave it open long enough and you'll start to see "camera shake" as well (which is the result of the fact that no person can hold anything absolutely steady -- we all move around involuntarily to some degree). The general rule is that you want your shutter speed to be at least 1/<focal length> in order to eliminate camera shake (assuming you're not using an image stabilized lens). At least, that's what works for full-frame cameras. For crop cameras, because the sensor captures a smaller part of the image circle, the general rule is 1/(1.5 * <focal length>;). And these days, the sensors are so densely packed that if you want to avoid visible camera shake when viewing the images at 100%, you really should use 1/(2 * <focal length>;). Your 40D isn't super-densely packed like the 7D is, so you can use the 1.5 version. An example would be, suppose you're using your 85mm lens. To avoid camera shake, you'll want your shutter speed to be no slower than 1/(1.5 * 85) = 1/125th of a second.

Aperture controls how much light is allowed through per unit time and also affects the apparent depth of field. The wider it is, the more light can come through and the shallower the depth of field. The aperture value itself is the ratio of the focal length to the diameter of the aperture (the "f" in the aperture designation is "focal length", so f/1.4 means an aperture size of whatever the focal length is divided by 1.4). An f/1.0 lens literally has an aperture with the same diameter as the focal length of the lens. There exist some 50 f/1.0 lenses out there, and their apertures, when wide open, are 50mm wide!

ISO controls how sensitive the sensor is to light. The more sensitive you make it, the less light it takes to achieve the same tonality in the shot. However, and this is oversimplifying quite a bit, if you amplify the signal generated by the light hitting the sensor, you also amplify the noise in the sensor and other electronics. Since you're bumping the sensitivity in order to be able to use less light to achieve the same tonal results, this results in a lower signal to noise ratio (since the "signal", or amount of light, is lower but the amount of noise remains more or less constant), and as a result the noise winds up comprising a larger portion of the tonal values you see than it would at lower ISOs (which would force you to record more light). And since noise is generally random, the result is a "graininess" in the tones. The noise has always been there, of course, but at low ISOs it comprises a small enough portion of the total signal that it's more or less invisible. That graininess isn't all bad -- sometimes it's desirable to make the shot look "film-like", and using a higher ISO can help achieve that (but then, so can adding noise after the fact).


A "stop" is a power-of-two difference between two values. When we use it in conjunction with photography, we're generally talking about the effect on exposure (more precisely, the effect on the resulting tonal values in the image). If we say we're opening the aperture by two stops, what we really mean is that we're opening it enough to cause the resulting exposure to be increased by two stops, which results in everything in the image being brighter by two stops, all other things being equal.

A shutter speed that is half that of another is one stop faster. A shutter speed that is 1/4 that of another is two stops faster. 4 is, of course, 2*2, which is also 2 raised to the power of 2 (or, written differently, 2^2). A shutter speed that is 1/8 that of another is 3 stops faster. 3 is 2*2*2, which is another way of saying that it's 2 raised to the power of 3, a.k.a. 2^3. You can see where this is going -- take 2 and raise it to the number of stops of change you want, and the resulting number is the factor you have to apply...

ISO is directly proportional to the sensitivity of the sensor. So if you want to change the ISO by a stop, you double (or halve) the number. ISO 200 is twice as sensitive as ISO 100 and thus requires that you cut your exposure by a stop in order to achieve the same tonality in your image. That means cutting your shutter speed in half (making it twice as fast) or narrowing your aperture by a stop (which means multiplying the f/number by 1.4).

Apertures are a little different with respect to the numbers. Remember that we're interested in the values that result in a change in exposure (in stops). Well, remember that the aperture value is the focal length divided by the diameter of the aperture. We're controlling the amount of light coming through the aperture by adjusting its size. But the amount of light coming through isn't proportional to the diameter of the aperture, it's proportional to its area. And the area is proportional to the square of the diameter. Which means that the amount of light coming through is proportional to the square of the aperture diameter. So if you want to double the amount of light coming through, you have to increase the diameter not by a factor of two (that would quadruple the amount of light coming through, because you'd take that factor of two and square it), but by a factor of the square root of two.

And so, the "next stop" of aperture is the result of taking the previous aperture value and multiplying it by the square root of two (or 1.4 for short). Which means the aperture progression looks like this:

f/1.0, f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22, f/32, f/44

See how each successive number is gotten by multiplying the previous one by the square root of two?

An easier way to think of it is to remember that you double (or halve) the number every two stops. If you can remember f/1.0 and f/1.4, you can derive the rest (the number after f/1.4 is f/1.0 times two, the number after that is f/1.4 times two, etc.).


I understand focus more thanks to your reply. I'm truly grateful for people like you who are willing to actually help instead of make judgmental remarks.

Thanks again!!

You're welcome. I just hope it helps!


"There are some things that money can't buy, but they aren't Ls and aren't worth having" -- Shooter-boy
Canon: 2 x 7D, Sigma 17-50 f/2.8 OS, 55-250 IS, Sigma 8-16, 24-105L, Sigma 50/1.4, other assorted primes, and a 430EX.
Nikon: D750, D600, 24-85 VR, 50 f/1.8G, 85 f/1.8G, Tamron 24-70 VC, Tamron 70-300 VC.

  
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philwillmedia
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Jun 28, 2010 03:51 |  #35

bananas13 wrote in post #10438510 (external link)
Well Phil, I'm a sophomore in college, I changed my major to photography this past Spring semester, and I've taken one photo class to date (an intro film class), and I start digital classes this Fall semester. I'm very eager to learn more in the meantime, and I think it's a little irrelevant to the topic to judge my lack of photography knowledge.

TheBurningCrown wrote in post #10438645 (external link)
Quite honestly I think it's your lack of photography knowledge which started this topic in the first place...

Agreed.
I wasn't judging you at all.
As I said earlier, I had assumed that you had some concept of the photographic basics given that you are doing a photography major.
I was thinking to myself wtf is going on here.
It became pretty obvious fairly early that your photography knowledge was somewhere between next to nothing and limited - there was nothing to judge about that.
You would have to agree with that, would you not?
Having done only one lesson of a beginners course was not what I was expecting.
So it is 100% relevant to the thread that you started.
It's pretty obvious that you are trying to learn and I was trying to assist that process.

You'll find plenty of help here if you are willing to take it on board, but you're going to have to develop a pretty thick skin and learn to take criticism of your photos and not take that personally - not everyone is going to be like your family and tell you that all your photos are absolutely wonderful.


Regards, Phil
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"A bad day at the race track is better than a good day in the office"

  
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egordon99
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Jun 28, 2010 07:33 as a reply to  @ philwillmedia's post |  #36

Basically, with flash, the FLASH exposure is solely determined by flash power (actually duration, how long the bulb is actually firing for), aperture and ISO. Ambient exposure is determined by ISO, shutter speed, and aperture (just like without any flash), so the trick is balancing the two. If I'm indoors in a smallish room (such as in someone's house), I usually just forget about ambient since the flash is powerful enough to light up the entire room (hence the 1/200s below, if the flash didn't fire, I'd have a more or less black picture) Now although you're shooting MANUAL Mode, that's only for the ambient exposure (the exposure needle in the viewfinder will blink warning you about underexposure, but ignore that). The camera's E-TTL metering will determine the needed flash output for a proper exposure.

Here's something I wrote on another forum -
"Easy" recipe for great E-TTL flash shots -
1)Point flash at ceiling/wall (to the side or behind you, experimentation is the key!)
2)Put camera in MANUAL mode on the mode dial
3)Set FEC to +1 on the flash head

4)Shoot RAW (this allows you to recover some highlights that might get blown as a result of #3 above)

5)Set ISO to 200 (to start)
6)Set shutter speed to 1/200s
7)Set f-stop to whatever DOF you want


Now if the flash runs out of "power" because of high ceilings, you can raise the ISO or open up the f-stop to compensate. Or you can slow down the shutter to bring more ambient light into the exposure (in addition to adjusting ISO/f-stop) If the ceiling is REALLY high (like in a church), you may need a reflector to throw some of the light forward (I use the Joe Demb Flip-it).




  
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egordon99
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Jun 28, 2010 07:34 as a reply to  @ egordon99's post |  #37

IF the flash is providing all the illumination (which it generally is in a small-ish room with you bouncing it off the ceiling), the shutter speed AND how dark it is do NOT matter AT ALL.

Try this - Pick a room in your house at night. Have a bunch of lights on. Set the shutter speed to 1/200s, aperture to f/5.6, ISO400. Point the flash straight up towards the ceiling (make sure the flash is in ETTL). Shoot.

Then turn off ALL THE LIGHTS, so it's pitch black. Do not change any settings. Take a picture. The picture should turn out the same, AND the flash wouldn't even have to work any harder. Basically, the flash is hitting the ceiling, and turning the ceiling into a large light source. THIS light source is providing all the illumination to the picture. How much flash power you need depends on the aperture, the ISO, and the distance from the light source to the subject. How dark the room is has NO affect on how much flash power is needed.

Now if you went with ISO400, 1/200,s f/5.6, and did NOT turn the flash on, the shot should be pretty dark, even with the lights on.

Now turn the flash back on, but adjust the shutter speed to 1/100s. The shot will probably look VERY close to the first two shots (you can turn the room lights back on now ) Then try 1/50s, 1/25s....Eventually you'll see the room lights "creeping" into the picture. This leads into the next paragraph...

A "flash picture" is made up of TWO distinct exposures. The "ambient" exposure if comprised of shutter speed, ISO, and f/stop. The "flash" exposure is comprised of ISO, f/stop, and flash power (and of course the distance from the light source to the subject) In the above example, the ambient exposure is essentially nil, so the picture is completely made up by the flash "components".

Once you nail using the flash to provide ALL the illumination, you can move onto more advanced topics such as balancing flash and ambient exposures.

you need to decide the CAMERA mode (Av or M, forget about using Tv/P auto modes) and the FLASH mode (Manual or E-TTL).

Indoors if the ambient light is fairly low and I'm using the flash to provide all of the illumination, I'll use M mode on the camera (and generally set the shutter speed to 1/250s to just get an ambient exposure) Outdoors where I'm using flash as fill (or indoors if it's bright, but this happens rarely) I'll use Av as I can rely on the camera to set a good general exposure WITHOUT flash, and then the flash can fill-in.

Now as for the FLASH mode, E-TTL works great if the flash is ON camera and you are constantly changing the distance between the light source and the subject. Now keep in mind what when you're bouncing, the bounce surface (ceiling or wall) actually becomes the light source. If you try to go Manual flash, you'll be adjusting the flash power for pretty much every shot, and this just isn't practical. E-TTL will get your flash power "in the ballpark"

Now once you get the flash OFF-CAMERA (on a light stand and shooting into/through an umbrella), Manual flash makes sense because although YOU can change the camera position, the light source is NOT moving (unless you move the stand of course), and as long as the subject(s) stay in the same general area, the subject-light source distance is constant. I'm talking portait/formals setups here.

Hope that helps!




  
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egordon99
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Jun 28, 2010 07:45 |  #38

bananas13 wrote in post #10437385 (external link)
1/20 sec | f/2.8 | 50mm | 1600 ISO | AV mode | "Pattern" metering | Tamron 17-50mm f/2.8 VC lens
580EX fired direct (w/ Lumiquest mini softbox) - ETT-L mode
Now that I look at my settings, I see why this turned out so awful... but wouldn't a flash compensate for the low light?

The flash did expose the subject fine. Don't use Av mode unless you want a shutter speed to fully expose the ambient light. Better to use Manual mode.

Mind you, I'm really new to flash photography and I still have a lot to learn about my camera settings in general.

Same settings as above except 1/30 sec and 31mm.
I know that it back-focused, but I have like 5 shots of the bouquet throwing and they ALL focused on the back like that... I would have spot metered, but I didn't have time to change settings... do wedding photographers just have to think on their feet like that? I just kinda figured it would auto focus on the closet object to me =/

First off, spot metering has nothing to do with focusing. Metering and focusing are two mutually exclusive concepts. Secondly, yes, wedding photographers DO just think on their feet like that. As for where it focuses, unless you tell it WHERE to focus (by explicitly selecting ONE focus point), it's a cr*pshoot as to where the camera will focus (and you can't come back and complain that it didn't read your mind)

I bounced my 580EX off the ceiling
I'm just sad because I want so badly for my images to come out sharp, and they don't... what am I doing wrong?

To snap a great shot in low-light with flash, there's LOTS of little things that all have to come together and you do NEED to be able to look at a scene and quickly (in a matter of 1-2 seconds) ascertain HOW to setup all those little things. What does the ambient look like? How are the walls/surfaces in terms of distance from flash to surface (and back to subject) as well as color/reflectivity. Are the subjects moving? Are there any windows with light coming in? How much DOF do you want? Do you want some ambient light in? Are the surfaces such that you can light up the whole scene with just the flash? Where do you want your focus point?

As advanced as camers are today, they still require quite a bit of operator input.

So I now realize that it's probably me, not my camera... I'm just frustrated. I'm still learning and I want to learn everything there is to know all at once, and I know that can't happen.

Can anyone help me out a little?




  
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arkphotos
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Jun 28, 2010 07:59 |  #39

really silly question ...
Is AF on the lens turned on?


1.6 crop & some lenses

  
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egordon99
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Jun 28, 2010 08:18 |  #40

arkphotos wrote in post #10439491 (external link)
really silly question ...
Is AF on the lens turned on?

I'm thinking it is...There was one shot where the lens clearly focused on the wall in the back. I'm pretty sure they just had the CENTER point selected and never paid attention to WHAT was in the center of the frame.




  
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ingraman
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Jun 28, 2010 10:40 as a reply to  @ egordon99's post |  #41

Actually, some lenses do have "infinity" focus. Never really understood what it does, but it was on my Tamron 17-50.




  
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egordon99
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Jun 28, 2010 10:44 |  #42

ingraman wrote in post #10440308 (external link)
Actually, some lenses do have "infinity" focus. Never really understood what it does, but it was on my Tamron 17-50.

ALL lenses can be "focused to infinity" but that doesn't help when you're trying to get multiple close subjects sufficiently sharp.

The basic problem is that the camera focused on the background instead of the near subjects, and she did not take depth-of-field into account when selecting the aperture.

You generally want to focus to infinity when doing landscape shots. Also, read up on "hyperfocal distance"...But you generally don't care about "hyperfocal distance" when shooting people dancing at a wedding ;)




  
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scottycam
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Jun 28, 2010 19:52 |  #43

I just read the OP's post and in case someone hasn't mentioned yet, there's a known issue on teh 40d with the shutter release button. Sometimes, when you press it down, it won't take but if you press down harder, it will eventually take the shot. Basically, its not instant when you press it. Anyways, the issue is that there's dirt/grime where the contacts are under the shutter release button. The quick fix, spray some circuit board cleaner onto a q-tip, then around the release so that the cleaner seeps in, then push it down and spin to rub it off.. Or you can send it to Canon. Good Luck.


"I once complained of having no shoes til I met a man who had no feet"

  
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thesloc
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Jun 28, 2010 19:56 as a reply to  @ post 10437831 |  #44
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How exactly are you a photography major?


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siginu
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Jun 28, 2010 20:02 |  #45

thesloc wrote in post #10443585 (external link)
How exactly are you a photography major?

This has been covered - do you have anything constructive to add?

The OP will likely take some of the advise and attempt to apply it piece by piece just like the rest of us.

Hoping to see some improved work posted in the future.


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