"AE - Auto Exposure, a system for automatically setting the proper exposure according to the existing light conditions. The most common types of AE systems:
Programmed where the camera picks the best shutter speed and aperture automatically
Program Shift same as Programmed plus the user can "shift" to other combinations of aperture and shutter speed values
Aperture Priority, the user chooses an aperture value and the shutter speed is automatically determined by lighting conditions
Shutter Priority, the user chooses a shutter speed and the aperture is automatically determined by lighting conditions"
"Auto Exposure
The camera automatically calculates the best aperture-shutter speed combination for lighting conditions. Typically, options include program or full auto (the camera selects aperture and shutter speed), aperture priority (user selects the aperture and the camera selects the shutter speed), and shutter priority (the user selects the shutter speed and the camera selects the aperture) modes."
And if you want to play silly dictionary games that include mincing technical jargon with rudimentary terms (manual-- in the non-tech sense), here is my entry in the Oxford American Dictionary, for autoexposure:
"autoexposure |?ôt?-ik?sp? zh ?r| noun
a device that sets the exposure automatically on a camera or other piece of equipment. the facility to set exposure automatically."
When you use a CZ 21, on an EF camera body, and you are in AV mode, the camera "sets the exposure automatically."
The key idea is that the camera adjust EXPOSURE... while it might adjust aperture, shutter, iso, or all three, those are simply the METHODS by which is achieves an EXPOSURE as determined by the camera itself.
jasonjoo wrote:
I think the Sigma 10-20 will work on a FF sensor. If it's not the 10-20, it's one of Sigma's wide angle lenses.
I have a 17-40 and the lens is all I could ask for. Well I wouldn't mind if it was a stop faster (ie: 16-35), but for the purposes of this lens, I hardly shoot wide open. Since it's mainly my landscape lens, I usually shoot with it stopped down. With a 1.6x crop camera, the 17mm end isn't EXTREMELY wide, but it can get the job done.
The three super wide angle lenses that I know of are (that work both on FF and crop sensors):
Canon 16-35
Canon 17-40
Sigma 10-20 (I think it's this one. It's one of the Sigma lenses for sure).
I'm not sure I know of any other wide angle lenses that work with both a crop and FF sensor....Show more →
Actually, if you are planning on going full frame, the Sigma 10-20 will vignette on the wide end. If I were going to go full frame, I would be looking at the Canon 16-35mm or the Sigma 12-24mm. Remember that on the 30D (a 1.6 crop factor) the 10mm end of a lens is equivalent to 16mm.
Sigma 12-24, Canon 16-35/17-40, Canon/Sigma/Tamron 14mm work FF.
But to be honest, it's not like your EF-s lenses, or non-FF lenses will lose their value if you ever go to sell them for an upgrade to FF. I don't understand this argument?
1.6 crop probably outnumbers FF by 1000 to 1... if not more. There's a major demand for EF-s lenses, and even if they stopped making 1.6 crop cameras tomorrow (which isn't happening ANYTME soon... did you read Chuck W's comments?), there will still be a bigger 1.6 crop market than FF for years to come.
If you want wide, I'd steer you towards Sigma 10-20 or Canon 10-22. Vignetting is easily fixed in PS, and in 90% of cases isn't noticeable... or looks nice.
"And if you want to play silly dictionary games..."
You haven't changed my mind. But thanks for the effort, even with your insult. Maybe I'm seeing something you're not and just not doing a decent job of communicating what I'm seeing. That's my fault.
"You're simply confusing auto-stop down with auto-exposure. The terms are independent."
Not confused as to me, they're the same. You can't have one, without the other. But that's my view. If it will make you feel better, write me off as a loon. It'll save you grief.
Yes, I read your posted material and came away with a different interpretation. In truth, all we can do is post our "silly" information and get on with it, being civil as we go.
As I wrote, I'm going keep on posting my view that you lose the AE when using the CZ21/2.8 and the choices are, get used to it or go crazy over the issue. I'm not changing my view on this matter. I do thank you for your efforts to convince me otherwise.
BeeMan458 wrote:
As I wrote, I'm going keep on posting my view that you lose the AE when using the CZ21/2.8 and the choices are, get used to it or go crazy over the issue.
I don't know what to say Beeman-- you're entitled to your opinion, even if everyone else knows it is wrong. But realize, you are disseminating misinformation... we can't stop ya.
OP-- if you choose to go the 3rd party route (the CZ 21 is $$ prohibitive, but OLY and others are not as prohibitive), you wont have any problems with ae, AV mode, or metering. None of these lenses will likely make much sense for you to pick up for applications that require AF, but for landscapes, or manually focused shots, you can find some gems and should not count them out.
"But realize, you are disseminating misinformation... we can't stop ya."
And I'm of the opinion that I'm disseminating truth. It would be wrong of me to disseminate misinformation. I think you guys are twisting things to suit your purposes. I think you guys will change definitions so it will serve your purposes in this matter. If it helps, I have a CZ85/1.4 and adapter and consider it a fully manual lense with no AE capabilities and lots of CA. But that's my view.
Manual focus and manual stop-down aperture and you guys want me to believe that it has AE. Okay. Sure. Ain't gonna happen.
huhhh? What are you guys arguing about? Auto stop-down means the camera controls the aperture, not you. Auto exposure is the camera setting your exposure, not you. How are those the same thing?? When I shoot a non-Canon lens on my Canon camera I retain auto-exposure (TTL metering) even though I have to manually stop down the aperture. What's confusing about that? How am I getting auto exposure out of Leica Summicron on my Canon body when the body has no way of stopping down the lens? Maybe I'm just too bored to read what started this pissing match, but one of you is clearly wrong.
>>"You're simply confusing auto-stop down with auto-exposure. The terms are >>independent."
>>Not confused as to me, they're the same. You can't have one, without the >>other. But that's my view. If it will make you feel better, write me off as a >>loon. It'll save you grief.
>Manual focus and manual stop-down aperture and you guys want me to believe that it has AE. Okay. Sure.??
Ok, maybe I am really stepping into something I shouldn't, but what the heck do you call AE? With an EF lens in aperture priority mode you set the aperture and the camera automatically stops down the camera right before triping the shutter and the AE function sets the correct shutter speed. With a non-EF manual lens you manually set the aperture and then the camera selects the correct shutter speed. How isn't this AE?
Granted, on some bodies, the exposure will be wrong
"When I shoot a non-Canon lens on my Canon camera I retain auto-exposure (TTL metering) even though I have to manually stop down the aperture."
I think I'm starting to see the confusion.
Auto-exposure; the camera controls the whole shooting match as opposed to in camera metering (TTL metering) and you can go Av but the camera still stops down and opens back up for you. The hand isn't involved in anything more then choosing the aperture with the thumbwheel.
In the beginning, many decades ago, it was called in camera metering or built in metering, not "auto-exposure" as nothing was being set or exposed. You had a little needle floating around inside the VF and had to manually set your "exposure" or "settings." Auto exposure came along around 1970 taking these functions over and it seems that this term has been twisted to include one or the other as opposed to both.
Nope, ain't going there as auto is auto and once the hand is involved, it's downgraded to manual. I don't mind looking the fool when I know I'm write even if everybody else is wrong. Don't matter to me as that's the nice thing about getting old.
Please, I've tried exiting yet you folks keep dragging me back in as it's considered polite to respond to comments. Call it like you want and I'll do the same. Seems fair enough.
-------------------------------------
"With an EF lens in aperture priority mode you set the aperture and the camera automatically stops down the camera right before triping the shutter and the AE function sets the correct shutter speed.
You got it right in the first part.
"With a non-EF manual lens you manually set the aperture and then the camera selects the correct shutter speed. How isn't this AE""
"...you manually set the aperture ..."
It's no longer AE once you manually do anything. AE covers the whole shooting match, not just a selected process of your choosing. I ain't the goofy one. Auto is auto and manual is manual and if the body don't stop it down and open it backup again, then it's no longer AE.
I had nothing to do with deciding definition of words or how they would be used. "Auto" and "Manual" both have well defined and understood meanings. I'm not going change the English language to suit the convenient nature of folks. Ain't gonna happen.
Edited by BeeMan458 on Dec 05, 2006 at 08:19 PM GMT
I've used both the 16-35 L and 24-70 L and find both to be softer than my inexpensive Canon EF 24mm f/2.8 at all apertures. I sold the 16-35L (overpriced for the quality), and although I have the 24-70 f/2.8L available at my workplace, I would never purchase one for my personal business. I'd rather use the 24mm and the 50mm f/1.4. The combined cost of those two primes would be less than half of what you'd pay for the 16-35L or the 24-70L.
If your priority is getting crisp images, avoid the wide angle zooms. If you are willing to satisfy crispness for the zoom feature, then the 16-35 or 24-70 will make you happy. But if I'm going to pay $1,000+ for a piece of glass, I sure as hell don't want to stop it down to f/8 before the images get sharp.
fine, my "automatic" finger manually sets my aperture with the thumbwheel for EF lenses and my "manual" finger sets my aperture on a manual lens... now your "logic" is crystal clear!
Still, in both cases the camera "automatically" sets the shutter speed... well mine does anyway... but somehow your's automatically "manually" sets your shutter speed... hmmm...
"fine, my "automatic" finger manually sets my aperture with the thumbwheel for EF lenses and my "manual" finger sets my aperture on a manual lens... now your "logic" is crystal clear! "
No, you're about as muddied as muddy can get. Your auto finger "chooses" the aperture, it doesn't "set" the aperture as the body "sets" the aperture which you tell it to stop down to. There's a difference between choosing and actually setting.
In an automatic transmission, it can choose the gear or you can choose the gear but the transmission still sets the gear. In a manual shift, you actually move the barrel over the gear teeth so the gear is engaged. There is a a difference and you guys just don't want to acknowledge the difference between choosing a f/stop and letting the body stop the lense down and actually stopping the lense down by hand; manual.
Old dogs apparently can't learn new tricks and, in case case, learn old tricks either.
You continue to fail to see the very real distinction between auto aperture and auto exposure.
As explained by myself and several others, AE has to do with the camera automatically determining the correct exposure. Automatically controlling the aperture is a convenience but not a requirement for AE.
This is a well known fact, both as defined by the dictionary and widely known in the photography world. You have obviously not taken the time to search for "stop-down AE" so I will now provide a few references of this:
Next would be Nikon 17-35, Leica 19mm, Zuiko 21mm.
If you want to have AF, then the choices are unfortunately more limited.
The best AF ultrawide for FF IMO is the Sigma 20mm 1.8. Terrible vignetting at wide apertures, but that's fixable in software. But the Sigma actually has detail in corners, as opposed to Canons.
Sigma 12-24 is excellent if you find a good copy. Not super-sharp in the center, but very consistent across the frame. Also, it's crazy-wide. I also heard good things about the Sigma 15-30.
Canon 17-40, 16-35, 17-35, Sigma 17-35 and Tamron 17-35 are all good in center but horrible in corners, unless you stop down to f/13 or so.
Sigma 15mm fisheye is awesome, but it's a fisheye.
If it helps, sometimes sitting up in a tree by yourself, is a good thing. 
?? When I shoot a non-Canon lens on my Canon camera I retain auto-exposure (TTL metering) even though I have to manually stop down the aperture. What's confusing about that? How am I getting auto exposure out of Leica Summicron on my Canon body when the body has no way of stopping down the lens? Maybe I'm just too bored to read what started this pissing match, but one of you is clearly wrong.