My first "L".

[Drk Orange]

Greetings all and sundry. I am the proud owner of a 24-70L, and have been so now for a total of just over 24 hours.

In my brief posession of this fine piece or engineering, I have realised why they are held in such high regard, it is truely awesome.

However...

It seems to be underexposing on my 300D by about a stop. Here's an example:

Uncompensated jpg taken from a RAW image:

http://members.iinet.net.au/~miketz/pics/Shells_dark.jpg

The same image after adjusting up one stop in photoshop:

http://members.iinet.net.au/~miketz/pics/Shells_light.jpg


The other standard lens that came with the camera and my 100mm f2.0 have been working perfectly for the last 18 months, so I am pretty sure it is the lens that is causing the problem.

What is the best way to sort out the problem?

BTW, here's the full adjusted image of the above image for those wanting to see just how good these lenses are...

http://img5.imagevenue.com/img.php?loc=loc119&image=6fa_CRW_0213a.jpg

[I Simonius]

Greetings all and sundry. I am the proud owner of a 24-70L, and have been so now for a total of just over 24 hours.

In my brief posession of this fine piece or engineering, I have realised why they are held in such high regard, it is truely awesome.

However...

It seems to be underexposing on my 300D by about a stop. Here's an example:
snip

First shot doesn't look underexposed to me, just needs a bit of contrast adjustmentt perhaps
It may not be what YOU visualised, but as far as 18% grey goes ot looks about spot on!
Best way to tell if the exposure is on or not is to look at the levels in photoshop.

Congrats on the new lens!

[Dante King]

It seems as the shell pics are OOF.

[Drk Orange]

>>It seems as the shell pics are OOF.

Out Of Focus? I'll take your word for that - but it's the best I have been able to get out of this camera. And it was hand-held to boot.

While this image may not be the best example of the exposure problem, the problem is there and everything just comes out a little too underexposed for my taste. Is it my taste or the lens that is not correct?

Here's another example, this time a *bright* yellow flower:

http://members.iinet.net.au/~miketz/sssf/FlowerA.jpg

[tim]

When you're taking photos of lightly colored objects you need to increase the exposure compensation by 1-2 stops. This is because of how camera metering systems work - it assumes all scenes are 18% grey. The flip side is if the scene is mostly dark you need to reduce your EC by 1-2 stops. It's an issue that wedding photographers have all the time, with the white dresses and black tux.

[Drk Orange]

The problem is noticable on all the pictures I take - including basically dark ones. (Which is where I first noticed it)

Here is a quick test:

An image of a bright stained-glass ornament against the sky taken with the standard 18-55mm lens that comes with the 300D:

http://members.iinet.net.au/~miketz/pics/55.jpg


A quick lens change to the 24-70L:

http://members.iinet.net.au/~miketz/pics/70.jpg

Both images were shot on aperature priority and focused on the same spot (a section of the lead)

To me, the 55mm shot is exactly how I would expect it. The 70mm is underexposed.

[tim]

The sky's very bright, i'd think you'd need positive exposure compensation with that. The brightness of those two images is pretty close, half a stop perhaps, it's hard to compare them given you used different apertures. Maybe reshoot that, or something else, at the same aperture for each lens? Not sure why they're different brightnesses, but like I said they're pretty close.

[I Simonius]

The problem is noticable on all the pictures I take - including basically dark ones. (Which is where I first noticed it)

Here is a quick test:

An image of a bright stained-glass ornament against the sky taken with the standard 18-55mm lens that comes with the 300D:

http://members.iinet.net.au/~miketz/pics/55.jpg


A quick lens change to the 24-70L:

http://members.iinet.net.au/~miketz/pics/70.jpg

Both images were shot on aperature priority and focused on the same spot (a section of the lead)

To me, the 55mm shot is exactly how I would expect it. The 70mm is underexposed.

There unlikely to be anything wrong with your cameras ability to expose correctly.
Those pics tell methat it's exposing OK.
WHY? Because the camera tries to make the pretty much WHOLE scene average out to 18% Grey. To get accurate exposure you need to take an exposure when the subject FILLS the frame. Then with that setting move back and recompose and focus.

So- Flower shot - the dark background has affected the exposure -the camera has evened out the exposure for the dark background and the bright flower and come up with an average - if you were closer to the flower the exposure would be nearer what you'd expected.- the same with the other shots, varying amounts of light sky will affect the exposure

If you are going to be shooting food professionally it will improve your shots to learn more about exposure - don't do it on auto.

The best way to tell quickly if the exposure's on or off the mark is to shoot somethinng with a CONTINUOUS tone, like EVENLY lit grass, or an evenly lit brick wall, making sure it fills the frame and that there are no bright reflections anywhere. Don't try it with flint, (too light) or slatye (too dark), you could also use an evenly lit carpet or unpatterned towel. Make sure you FILL the frame with it.

A trick I use whenn I'm dubious about the auto exposure is to meter off my hand in the same light as the subject and open up one stop. (ie.e.fill the frame with the palm of my hand) That's usually fairly accurate. Why open up one stop ? because my the caucasian skin tone of my hand is one stop lighter than 18% grey, which is what the camera is set to make every exposure come to, so it makes my hand one stop darker than it is, bringing it up to 18% grey, by opening it up one stop I'm bringing it back to the right exposure

Once you know tthat your camera IS exposing properly for 18% grey and there's nothing fundamentally wrong with it, then it's a question of understanding HOW it arrives at an exposure so you can correct it when it doesn't match what you visualise. Most still life professionals have an exposure meter or an 18% grey card - or both - just because of the very problem you are experiencing.

[Drk Orange]

Well, I have gone back and re-shot some of the photos I did the other day and they have turned out OK, so it is maybe just the 300D getting confused temporarily. (Which is probably why I found it hard to recreate the problems I was getting)

It is about 18 months old and that is the second strange thing it has done within 2 weeks, so maybe it is time to upgrade the body. ;)

Thanks for all your help.

[I Simonius]

Well, I have gone back and re-shot some of the photos I did the other day and they have turned out OK, so it is maybe just the 300D getting confused temporarily. (Which is probably why I found it hard to recreate the problems I was getting)

It is about 18 months old and that is the second strange thing it has done within 2 weeks, so maybe it is time to upgrade the body. ;)

Thanks for all your help.

who's body? ;) ;)