Edumacating my hubby on exposure triangle

[faeriegodess612]

So,.. I was going over the beginner tutorials here, refreshing my memory for when I do get my camera. Since the exposure triangle is something that I havent had to think about much with my P&S. So,..I was reading the one on aperture and the examples given I was thinking as I read it, "Ok,.. so larger f/stop means larger DOF, and smaller f/stop means smaller DOF." Then come across that line pretty much exactly. And I said something about how it seems that its backwards. ( I know thats how it actually works, but it does seem weird) Seems like a smaller aperture would mean a smaller DOF, and vise versa, but thats not the case. I mentioned this to my husband, and then that got us into a debate. Why? Cuz he goes,..
"Yeah, but thats all digital stuff."
"Uh, no, thats every SLR." I tell him. "The only real difference between a SLR and a DSLR is that an SLR takes the image and puts in on film, and a DLSR takes the image, then stores it on a memory card."

Besides of course the obvious stuff like Film Speed = ISO, and you can see the image as soon as its taken, and the features that are offered on a digital camera that arent possible on a film camera. The science of it all is still the same. Although apparently the new film SLR's can change the ISO. I went to grab hubby's Canon EOS Rebel K2, that he bought years ago when he was in college. For his Art credits he chose photography. I learned tonight that most of what they taught them in Photography I (One) was how to develop the film. So, I pointed out the different modes,...M= Manual; Tv= Shutter Priority Mode; Av= Aperture Priority Mode,...etc. That aperture was something that EVERY camera has,... you just dont always have control over it. He didnt have much to say after that, but then changed the conversation to another aspect. The ISO. Basically his way of saying "Ok,.. maybe you do know more about this than me" without actually saying it. lol, Love it when I can prove him wrong.

Just had to share,..mind you we werent arguing, just debating. We'd never argue over something so trivial.

[tuxcomputers]

I thought he was deployed OS?

[nickbedford]

You may be confusing the difference between aperture size and f-stop. It's easy when you forget that the f-stop is the divisor in the equation. Focal length divided by f-stop equals the physical size of the aperture. Small aperture is the result of a large divisor (f-stop).

A smaller f-stop (i.e. f/1.8) gives a larger aperture and a smaller depth of field.

A larger f-stop (i.e. f/11) gives a smaller aperture and a larger depth of field.

Then you must also not confuse "large" depth of field with "large" blur. These are anti-proportional. This is a good illustration of why a large aperture creates a small depth of field and visa versa.

Fileepth of field illustration.svg - Wikipedia, the free encyclopedia

Also, ISO actually applies to both film and digital sensors. Think of the ISO as the "multiplier" to achieve the same general result with a given aperture and shutter speed.

So a small sensor compact at ISO 100 may actually be amplifying the signal more to achieve the same brightness than ISO 100 on a DSLR due to it's inability to capture as much light as the DSLR. In other words, 1/250th, f/2.8 at ISO 100 should generally achieve a similar exposure on all cameras.

[faeriegodess612]

Originally Posted by nickbedford

You may be confusing the difference between aperture size and f-stop. It's easy when you forget that the f-stop is the divisor in the equation. Focal length divided by f-stop equals the physical size of the aperture. Small aperture is the result of a large divisor (f-stop).

A smaller f-stop (i.e. f/1.8) gives a larger aperture and a smaller depth of field.

A larger f-stop (i.e. f/11) gives a smaller aperture and a larger depth of field.

Then you must also not confuse "large" depth of field with "large" blur. These are anti-proportional. This is a good illustration of why a large aperture creates a small depth of field and visa versa.

Fileepth of field illustration.svg - Wikipedia, the free encyclopedia

Also, ISO actually applies to both film and digital sensors. Think of the ISO as the "multiplier" to achieve the same general result with a given aperture and shutter speed.

So a small sensor compact at ISO 100 may actually be amplifying the signal more to achieve the same brightness than ISO 100 on a DSLR due to it's inability to capture as much light as the DSLR. In other words, 1/250th, f/2.8 at ISO 100 should generally achieve a similar exposure on all cameras.

WOW! You think of things in a much more complex manner than I do. Your giving it a mathmatical equation and my brain doesnt work in math. My subject was English. I dont need to know how or why that a larger f/stop gives a larger DOF even though that means that the aperture creates a smaller opening,...just that it does, and how to use it. I assume its almost like facing the sun and trying to see past 5 feet in front of you, then putting on a pair of sunglasses and being able to see 50 feet in front of you. The less light coming into your eyes, the further you can see. But you essentially just said what I did. Just worded differently. If you look at part of what you just posted, its pretty much the same.

"A smaller f-stop (i.e. f/1.8) gives a larger aperture and a smaller depth of field."
Yes, the smaller the f/stop (f/1.8) the smaller the DOF. If you take out the middle portion of that sentence its the same as what I said. The larger the f/stop (f/11) the larger the DOF.
Just to let you know,..I'm not trying to argue, and I know your not either. I think that we think of it in different ways so that it makes sense to each of us.

To Tux: Nope, hubby was in Cali for training. They send them out on this stupid "refresher course" essentially a few months before they deploy. Might work for the guys on the front line, but hubby already has all the training hes going to need for what he does. Hes an electronics tech, and pretty much stays on base. I'm going to be more concerned of him getting hurt in a convoy from an IED ( cuz hes trained in how to drive some of the military vehicles ) than from getting shot at. He deploys in February.

[NicoleScraps]

I'll tell you one thing, if I was you, I'd be all over that SLR camera. It would be called MINE!

[nickbedford]

Originally Posted by faeriegodess612

I assume its almost like facing the sun and trying to see past 5 feet in front of you, then putting on a pair of sunglasses and being able to see 50 feet in front of you.

I'd say that that analogy isn't correct.

Think of the limitations on angle of light coming through the lens. When you have a large aperture, out of focus light can come in from crazy angles left and right, up and down compared to the pointing direction of your camera.

This makes the out of focus areas blur heaps because of all the extra light from much larger angles, whereas with a small aperture only more straight-on rays of light can enter the lens and thus the radius of the blurred light becomes less and thus more of your scene appears in focus.

Sorry if I'm confusing you, it's just easier when you have a correct understand of what is actually happening. I find it better to have a true understanding of why things are happening the way they are instead of just going off the "observations" of cause and effect with regards to aperture and shutter speed etc.

[navcom]

Nick's right....but dude! You need to get out more! All that thinking will melt your brain!

..just giving you a hard time.

[faeriegodess612]

Originally Posted by navcom

Nick's right....but dude! You need to get out more! All that thinking will melt your brain!

..just giving you a hard time.

+1,..LOL. Good grief Nick. Like I said buddy, I dont need to know the science behind how it works, just that it does and how to use it. Ok,..so maybe that was a bad example. It was my spur of the moment theory as to how it might work. I never took apart my toys to see how they worked,...I was just happy that they did, and that they were fun to play with.

Nicole: I tried using it. (The SLR) but found myself wanting to look at the screen after I took a picture to see how it looked. Then the more I thought about it, the more I was just like,..OK, I cant justify this. I'm not one of those photographers that just points and clicks,.. I make sure that a shot looks exactly the way that I want before I press the shutter release. BUT,..I just couldnt do it,... not to try and learn with. Maybe when I get more accustomed to my Dslr, ( when I get it )..then I might use the film that I bought for the thing.

[deck]

Originally Posted by faeriegodess612

That aperture was something that EVERY camera has,...

Aperture is inherent to the lens, in old lens models you control the aperture via aperture rin on the lens, in newer film cams and dslrs it's controlled via camera with some exemptions...

Regarding the difference between digital and film, the science of taking the exposure is pretty much the same, exposure triangle works with both film and digital takes, ISO is a different term for ASA but both means sensitivity sensor/film.
Optics is also the same except for some difference in DOF in some cameras due to crop factors (i.e. the smaller the sensor the less the DOF)
In terms of image quality in my opinion the digital field is still catching up in terms of resolution, but in sensitivity (ISO) it has gone leaps and bounds.

Also, there are certain color correction filters for film cameras that are not very much used anymore since certain cameras offer the function for color correction...

Hmm...
That's all I can think of right now, I hope this helps in your debate, hehe