Kit lens pics darker than standard lens or Sigma...

Hi,

I just got my new Canon 400D a fey days ago and I took the first shots from my window today in order to compare the three lenses I bought.

The first two pics were taken with the kit lens and you can see them here:

http://www.picture-this.de/thumbnails.php?album=133

are darker than the pics taken with the Sigma and with the standard lens. The camera was mounted on a tripod and shots were taken exactly from the same spot.

Anybody know why this has happened? I'm a bit puzzled.

Thanks.

Hardy

--
http://www.tepfer.com

Hardy said:

Hi,

I just got my new Canon 400D a fey days ago and I took the first
shots from my window today in order to compare the three lenses I
bought.

The first two pics were taken with the kit lens and you can see
them here:

http://www.picture-this.de/thumbnails.php?album=133

are darker than the pics taken with the Sigma and with the standard
lens. The camera was mounted on a tripod and shots were taken
exactly from the same spot.

Anybody know why this has happened? I'm a bit puzzled.

Thanks.

Hardy

--
http://www.tepfer.com

Click to expand...

Yes, I have seen the same but don't really know why.

I remember buying a 28-70 mm years ago for my Pentax film SLR and found that it was darker and caused the exposure to drop at least 2 stops compared to the standard lens. I then bought a 70-150mm lens that exposed at the same level as the standard lens. I suspect it may be the coating used on the lens glass.

Cheers.

Pic 2 is 1/200s f10 and pic 3 is 1/200s f8, so no wonder it is brighter. But how did you let the camera choose exposure?

Since exposure is determined while you are framing, with the aperture wide open, the metering sensors do get a different amount of light. If you use the kit lens around 50mm it is f/5.6 and a Sigma 24-70 for instance will be f/2.8 when the metering is done. When the metering sensor isn't "linear" it may guess wrong at what the exposure will be at f8. It shouldn't be different, and might be considered a defect if it is.

Hardy said:

Hi,

I just got my new Canon 400D a fey days ago and I took the first
shots from my window today in order to compare the three lenses I
bought.

The first two pics were taken with the kit lens and you can see
them here:

http://www.picture-this.de/thumbnails.php?album=133

are darker than the pics taken with the Sigma and with the standard
lens. The camera was mounted on a tripod and shots were taken
exactly from the same spot.

Anybody know why this has happened? I'm a bit puzzled.

Thanks.

Hardy

--
http://www.tepfer.com

Click to expand...

--

Slowly learning to use the DRebel (only around 26.000 shots) and now also the Fuji F11.
Public pictures at http://debra.zenfolio.com/ .

Hi,

I used the Tv mode and selected 1/200 and let the camera select the aperture. Yes, I noticed too that the darker pictures were made with a different aperture, but I didn't change any settings, this is what I was trying to say.

All settings are the same, but the pics from the kit lens are darker. Why? I mean, why did the camera select a different aperture for this lens? Shooting conditions were the same.

Hardy

--
http://www.tepfer.com

Hardy said:

Hi,

I used the Tv mode and selected 1/200 and let the camera select the
aperture. Yes, I noticed too that the darker pictures were made
with a different aperture, but I didn't change any settings, this
is what I was trying to say.

All settings are the same, but the pics from the kit lens are
darker. Why? I mean, why did the camera select a different aperture
for this lens? Shooting conditions were the same.

Click to expand...

That's not uncommon - some lenses tend to choose different exposure than others (hmm... maybe that's the reason of some underexposure complaints about the XTi)? Just learn the exposure characteristics of each lens by experimenting and compensate.

--
Misha

Thanks for the suggestion, Misha!

I will try that.

Actually, I took these shots to compare sharpness and thru this I found out that the kit lens uses a different aperture under same conditions.

Hardy
--
http://www.tepfer.com

Go to M mode and set the shutter and aperature yourself. Make the shutter the same, and then set the aperture so the exposure meter reads the same. See if that makes a difference...

James

misha said:

(hmm... maybe that's the reason of some underexposure
complaints about the XTi)?

Click to expand...

Interesting theory...

I think the inside camera software is trying to "guess” the right exposure fo a different f number. I think is not rocket science, but there could be a programming problem on Xti.

I was on the impression that the pictures taken with my 70-300 are brighter than those taken with 28-135…
I think now I’ll have to test this theory outdoor….
Another one (camera) bite the dust (on the sensor )

C

--
Cipri - Canon XtiRebel, EF 28-135mm f/3.5-5.6 IS USM, EF 70-300mm f/4-5.6 IS USM

Taming the XtiRebel is not a hobby. Is a life experience

http://www.ham.dmz.ro

Hardy said:

Hi,

I used the Tv mode and selected 1/200 and let the camera select the
aperture. Yes, I noticed too that the darker pictures were made
with a different aperture, but I didn't change any settings, this
is what I was trying to say.

Click to expand...

if you want to compare the lenses you should have used the exact same exposure value. true, "you didn't change any settings", but the camera did change the settings, that is why one picture wlil be darker/brigher than the other.

Hardy13337 said:

All settings are the same, but the pics from the kit lens are
darker. Why? I mean, why did the camera select a different aperture
for this lens? Shooting conditions were the same.

Hardy

Click to expand...

depending on what metering mode you are using, the camera may vary exposure values. i shoot in Av mode typically, where i select an aperture and the camera selects a shutter speed. when half-pressing the shutter release and looking through the viewfinder, you can see the selected aperture, and the camera's chosen shutter speed, and it will vary even on a static scene you can see it move up and down as the camera is trying to decide which shutter speed to go with. it doesn't lock in a shutter speed until you hold the shutter release at half-press.

also, little changes in the scene can affect the camera's chosen EV, again mostly based off your selected metering mode. simple things such as the positioning of clouds outside, or any changes in reflected light.

As others noted about mode used to meter and differences in the f stop from the exif info. One problem that any lens/camera combo would have with this scene is the difference in the sky and the buildings/foreground. There looks to be a 2-5 stop difference in what the meter would read when pointed only to the sky or to the buildings. The meter in the camera is again trying to make the scene "average" or 18% grey, so the end result would be a foreground darker than the sky of about 2 stops. How did you meter the scene? Evaluative, center, or spot would also have some influence on what the meter sees and tries to adjust for. To make an assumption that the kit lens is causing your meter to adjust differently just because you take a photo of the same scene under the same lighting is at the least flawed, when the total scene is not lighted evenly. Try it again with even lighting on the foreground and background and see if you get the same results, and if you do, then maybe the kit is exposing differently (underexposing) than the other lenses you have. robby