Official: T2i/550D

plawa wrote in post #11490761
I believe the algorithm depends on focal length, from my observation it will try and hit the usual shutter speed of 1/focal length.

From what I can find browsing, this seems right. The camera will first slow the shutter to get more light, until it hits 1/focal length. If that's not enough, it will increase ISO until it hits the maximum amount you've set. If you're using flash, ISO is fixed at 400 (this part is in the manual).

FWIW: I can't stand auto ISO unless I'm in wildly variable lighting for some reason. Most of the time, I prefer to run full manual, get the exposure close to what I'm after, then shoot a full set without changes. This makes the post processing go so much faster in DPP, because most of the images in a given set will take the same recipe.

If I'm in manual with auto ISO, I might accidentally meter off a black shirt instead of a gray one or whatever, and the ISO bumps up a bit. Now I've got a different recipe to develop that RAW. PITA.

As of now, I have found one usefull application for auto ISO. Sports.

When I'm shooting inside, I usually go wide open and select the shutter speed I want. Auto ISO will do it's job in exposing correctly each picture. Wheter it's a tight crop or a wider picture. Zoomed in or out. This way, I know my shutter speed will always be fast enough and I'll have the most subject isolation possible.

Apart from that, I never use auto iso

The best way to kill fungus and fungus spores is using UV Light.

You can't really use Bleach 10% Solution as it would ruin the lens finish maybe. Bleach is an oxidizing agent and the Chlorine CL- in the bleach is a very powerful chemical.

Let the lenses soak up some sun rays and that should cure the fungus up.

Keep the camera and equipment dry and at room temperature.

I have an old film camera that I stored in a dark closet and inside a big leather camera bag and some of the old film camera lens cases started growing some fungus on the case. Cases were made of cardboard or leather or some type of organic material.

I took a damp rag and wiped the fungus off and then put them in the sunlight for a few hours.

Just make sure that you cover any lenses with the lens caps so as not to let direct sunlight get into the lens. Lenses can act like a magnifying glass and start a fire sometimes if you don't protect them from the sunlight.

Have you ever tried to burn a leaf or paper using a magnifying glass and sunlight? The same effect can happen with a camera lens sometimes.

Just remember that fungus spores are hard to kill and are all around us all the time. So the trick to eliminate fungus is the keep the equipment in a controlled environment that is not condusive to fungal growth. Dry and well light by sunlight.

Hope this helps.

As for going from a cold environment to a warm house just wrap the camera equipment up to seal it from moisture in the house. I recommend using a 1 gallon double zip lock baggie to put the camera into. Seal it up and put it inside a camera bag and then bring it into the house and let the equipment warm up gradually to prevent moisture condensation on the camera equipment.

Warm air holds a lot more moisture than cold air. And any moisture in the air will condense out on a cold metal object and coat the surface with water. So keep the equipment away from the air moisture until it's equilibated to room temperature.

This way your T2i camera and lens will stay in tip top shape longer.

DH22 wrote in post #11326660
I just recently got this camera and trying to learn about DSLR I heard about lens fungus for the first time. Is this something to be concerned about? I would like to protect my lenses and cameras since they are major investments but also want to enjoy them without constantly worrying about infections.
The other day I was shooting in fairly cold and windy weather and when I brought it in my home the camera was cold. I'm thinking the camera might have gotten some internal condensation from quick temperature changes.
How do most of you prevent fungus growth on your gear? Best practices to use?

waterrockets wrote in post #11492210
FWIW: I can't stand auto ISO unless I'm in wildly variable lighting for some reason. Most of the time, I prefer to run full manual, get the exposure close to what I'm after, then shoot a full set without changes. This makes the post processing go so much faster in DPP, because most of the images in a given set will take the same recipe.

If I'm in manual with auto ISO, I might accidentally meter off a black shirt instead of a gray one or whatever, and the ISO bumps up a bit. Now I've got a different recipe to develop that RAW. PITA.

True but you can set the auto iso upper limit. The question about shutter speed vs iso is a very good question. But if I don't want the noise I either set the iso manually or tweak the auto iso setting limit.

kenshap wrote in post #11494306
True but you can set the auto iso upper limit. The question about shutter speed vs iso is a very good question. But if I don't want the noise I either set the iso manually or tweak the auto iso setting limit.

Good to know about the limit. FWIW: my beef isn't with how high the iso goes, it's just that it changes when my lighting hasn't changed. I use spot metering, meter on the sky, grass, a card, etc. and I'm done with the exposure stuff for a set of shots. I don't want it changing and making more work for me in post.

Agreed though that if I'm panning more than 90 degrees during a set, or if clouds are coming and going, etc. auto ISO is fine. Static ISO fails to be a post-processing advantage because the lighting is changing all the time anyway.

How is the T2i at focusing in low light, especially when using a not very fast lens, such as the kit lens or the 55-250? Does it work well or do you have to use the flash for focus-assist? I'd think the flash would be very annoying, especially if you're shooting in museums, cathedrals or other buildings that don't allow flash.

It doesn't seem to focus that well in low light...but I don't imagine any are spectacular at doing so. No doubt the 7D is somewhat better.

Is the flash as annoying as it would seem to be when it's in focus assist mode?

The flash doesn't come on unless you either A. pop it open yourself or B. Have the camera set to automatic. I virtually never do either. It seems to me the "Focus Assist beam" comes into play some times, but it struggles, especially with the canon 50mm 1.8 which is notoriously bad in poor light, and limps along fairly well with other lenses. (I'm talking about really poor light, as in night-time outside with distant street lights.)
I got these on Saturday night with the nifty fifty. It did the job, but was a bit poky about it.

IMAGE LINK: http://www.flickr.com …s/tainanstuff/5​279314593/

IMAGE LINK: http://www.flickr.com …s/tainanstuff/5​279311229/

Mookalafalas wrote in post #11496764
The flash doesn't come on unless you either A. pop it open yourself or B. Have the camera set to automatic. I virtually never do either. It seems to me the "Focus Assist beam" comes into play some times, but it struggles, especially with the canon 50mm 1.8 which is notoriously bad in poor light, and limps along fairly well with other lenses. (I'm talking about really poor light, as in night-time outside with distant street lights.)

I'm trying to decide whether to buy the 550D. I take a fair number of pictures in dim light in places that don't allow flash and am worried that I'll have problems focusing.

Odd that the 50/1.8 is bad in dim light and other lenses (such as the 18-55 or 55-250?) do better. Usually a 1.8 would focus a lot faster than a 3.5-5.6 or a 4-5.6.

By the way, this is one of the most helpful threads I've seen on any topic on any photography forum. Informative, polite and on topic is a very rare combination.

richarddd wrote in post #11496982
I'm trying to decide whether to buy the 550D. I take a fair number of pictures in dim light in places that don't allow flash and am worried that I'll have problems focusing.

Odd that the 50/1.8 is bad in dim light and other lenses (such as the 18-55 or 55-250?) do better. Usually a 1.8 would focus a lot faster than a 3.5-5.6 or a 4-5.6.

By the way, this is one of the most helpful threads I've seen on any topic on any photography forum. Informative, polite and on topic is a very rare combination.

I haven't shot a lot in really low light with my 550D. I do imagine the 1.8 would have more trouble if it's wide open because the DoF is so small. A minor focus error will really soften the subject a lot. With another lens at, say, 5.6, that's not as much of a problem.

FWIW, here's are a couple representative shots from a dim room at a 40 y/o birthday party. Lights were standard family room lighting, at night. Non-white walls too. You can see some softness in most of the shots that night. This was before I started shooting in raw, and I was generally new all-around, so excuse the other shortcomings I had some composition challenges with the 50mm too -- kind of a long lens with the crop sensor for shooting up close.

Mookalafalas wrote in post #11496154
It doesn't seem to focus that well in low light...but I don't imagine any are spectacular at doing so. No doubt the 7D is somewhat better.

Yes 7D is beter then the 550D. Love the AF of the 7D

waterrockets wrote in post #11498111
I haven't shot a lot in really low light with my 550D. I do imagine the 1.8 would have more trouble if it's wide open because the DoF is so small. A minor focus error will really soften the subject a lot. With another lens at, say, 5.6, that's not as much of a problem.

The lens would be wide open when focusing, only closing down to the set aperture when shooting. A 1.8 lens can close down to 5.6, but a 5.6 lens can't open to 1.8.

A 1.8 lens will provide the AF sensor a lot more light to use to focus than a 5.6 lens. Therefore, the 1.8 lens should AF better and faster, all things being equal.

When shooting, a 5.6 aperture will provide more DOF, so it will be more forgiving of focus mistakes.

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