Tamron 90mm weird ISO/display problem help please

alyphoto · Jul 29, 2011

I'm not sure if this is normal behavior but I would assume not I bought a new lens about a week ago for my Canon T2I. Tamron 90mm macro lens.

This one, specifically:
Amazon.com: Tamron AF 90mm f/2.8 Di SP A/M 1:1 Macro Lens for Canon Digital SLR Cameras: Camera & Photo

My problem is that it is nearly unusable in Manual mode unless I have the ISO on Auto. I'll try to explain what happens;

The image I see on the LCD is SIGNIFICANTLY darker than what the actual picture looks like once it's taken. The image on the LCD can be nearly black (shutter speed around 2-400), but the image taken will be normal or extremely bright. If the image on the LCD is of normal brightness (shutter speed 40-125), the picture that is taken will be pure white. The ISO can be on 100, 200, 400, 800, or any set number. Aperture is always at f/2.8 for shooting but for trying to figure out this problem I've tried 4,5,10, etc.

If I set the ISO to Auto, it seems to fix itself in that the image I see on the LCD is what I get when I take the picture, but then I run into grainy images because it likes to put it on very weird isos. Sunny outside, and it picks an ISO of 3700. Sometimes it will pick a proper value of 1-200 and the images are perfect.

If I put it on P, AV, TV or Auto it doesn't have this problem and I can set a set iso, but in those modes I can't adjust everything that I need to for macro shooting.

I like to use the LCD for framing my macro pictures because it's much easier for me to focus correctly, and it's currently impossible for me to do so unless I set the iso to auto.

Is this my lens, or my camera?? Is it defective? Or is this normal behavior?

D-B-J · Jul 29, 2011

It sounds like you are not exposing the scene correctly. Do you use your meter? I mean, if you put the iso at 400 and the aperture at 2.8 and the shutter speed at 1/40th on a bright day, it will be all white.

KmH · Jul 29, 2011

If the LCD hasn't done that until you started using the new Tamron lens, it's likely the lens. If the LCD does the same thing with other lenses, it's the camera.

alyphoto · Jul 29, 2011

I've tried all of the metering modes and none seem to help the issue.

On a bright day I would have the shutter speed in the 100-200's, but in order to see what I'm photographing on my LCD I have to change the shutter speed to something like 40. Then the image on the LCD looks normal and not extremely dark. But the taken picture, obviously, is white. The same thing happens inside under my desk lamps. So in order to frame a picture with the LCD, I have to first frame it with the shutter speed set to 40, and then change the shutter speed back to 200, and then take the picture. Obviously, for bugs or anything like that this is a pretty long process and I also have to make sure I don't move the camera or I will lose the focus and not be able to refocus unless I change the shutter speed again...

This is only on Manual. If I move the dial to p, with the same settings, the image displayed/taken is normal. But I can't adjust aperture there. It seems obvious that there is a setting in manual that is messing things up..or the lens doesnt work properly in manual. I just can't find out what it is.

KmH, yes, it's only the Tamron on ONLY in Manual mode.

Robin Usagani · Jul 29, 2011

damn.. i just ordered this. I hope it is ok.

alyphoto · Jul 29, 2011

Heres some image examples...

This is what I see (taken with another camera so colors are a lil off but you get the idea)

but this is the resulting picture

Obviously shutter speed of 30 is way too bright for that..but that's not what the LCD told me.
So here is a proper speed of 100.

with the resulting picture

The only thing that changed between the photos was the shutter speed

Robin Usagani · Jul 29, 2011

Then adjust your LCD? You can adjust brightness of your LCD.

Destin · Jul 29, 2011

Do you have the live-histogram (I think that's what it's called, I'm not a canon guy, but my best friend has a t2i) option on the LCD turned on? If not, the LCD isn't showing you the exposure, just the composition. You're taking all of these in Live View, correct?

Have you tried looking through the viewfinder to take a photo? How does it come out then?

My bet is that the setting, which allows the LCD to display a live example of your exposure in live view mode, is turned off. Or maybe for some reason isn't compatible with your lens. Regardless, you shouldn't be making exposure calls using the lcd, you should make them using the cameras meter.

alyphoto · Jul 29, 2011

Schwettylens, I actually didn't think of that. It did help quiet a bit but it's still darker than what the actual picture comes out as. Maybe it is usable like this, however, if it's a defective lens who knows what else will break with it

alyphoto · Jul 29, 2011

Destin, yes, it has a live histogram. I turned it off to take those pictures up there so that people could see the screen better. It doesn't effect the picture at all, though. I mean, the problems still happen.

None of this seems to explain why it only does this in manual mode, though? When I can use the exact same settings in any other mode and it won't do this. What I see on the screen is what I get. So saying my cameras lcd can't display something doesn't seem to be correct when it's doing it in other modes.
Looking through the viewfinder doesn't show changes to brightness or anything. So it's still sort of the same problem. While it looks nice in the view finder, I need to check the lcd to make sure the colors and brightness are correct..which aren't on the lcd, in manual mode.

Destin · Jul 29, 2011

Ok, your wording has me confused here, and it seems like the others are confused to.

I would love to help you figure this out, as I'm sure they would too.

If you could walk me through step by step what you are doing when this happens, it would help. Are you shooting in live view? Or just using the screen to review the image after you take it?

I'm going to bed, I'll be on sometime tomorrow if I can be.

alyphoto · Jul 30, 2011

Okay. Sorry, getting very frustrated with the lens so maybe I'm not being that clear

Pictures are the best way to explain what is going on, I think.

This is in AV mode with shutter speed 60, f/2.8, 800 ISO. And the picture I take looks just like the image that I see here.

This is on Manual mode with shutter speed 60, f2.8, 800 ISO. The picture that I take looks like the one above. But the image displayed on the LCD is very dark. To get it to display on the LCD like the one above, I have to make the shutter speed 25. But the actual picture I take is extremely bright, and looks nothing like what I see on the LCD.

This ONLY happens in Manual Mode. Every other mode, what I see is what I get. It's why I'm so frustrated.

The suggestions that the problem is that my camera cannot display the exposure in Live View mode do not seem correct because it does it just fine in all other modes. It is only in manual mode, that the LCD display is much darker than it should be. I do not even know if it is exposure settings or not.

Even if I up the brightness of the LCD it does not really solve the issue. Everything looks brighter then. While it does allow me to see the darker display better, the pictures taken are still lighter than what I saw, and having the lcd brightness up all the way makes everything look over exposed when it's not, and really isn't a fix to the problem.

For some reason, turning on Auto ISO in Manual mode seems to correct the issue to some extent. The image that I see on the LCD is the same as the picture that I get. However, it chooses really bizarre ISOs that is causing very grainy images. In the pictures above, if I put it in auto iso while in manual with all of the same settings, it will bump the iso up to 3700 which is a ridiculous amount for the lighting I have in here, and it is obviously not needed, 800 iso is fine. With the ISO on Auto, the image that I see on the LCD is how the picture turns out. Another weird thing about this is that if I manually set the ISO to 3700, it will go back to showing me an image that is darker than the actual picture that it takes. It makes no sense to me!! It's hard to explain, because I'm so confused myself. I'm starting to really thing the lens is defective in that it can't operate correctly in full manual mode, but all things that I read about this lens, I never read about that being an issue with the T2I.

This ONLY! happens with this new Tamron. I have 2 other Canon lenses that can function fine in full manual mode.
The only thing with the Tamron is that in manual mode the LCD is very dark, which doesn't effect actual picture quality, they turn out just as they should. It just makes it very difficult to focus/frame/adjust brightness and what not.
While I CAN use the Viewfinder, I usually don't want to, and I SHOULD be able to use the LCD in Liveview, but there is something that is causing a problem. If I can't because there is a problem with the lens... I don't want to keep it anyway.

Robin Usagani · Jul 30, 2011

Yeah.. that is weird. I dont know what is going on.

alyphoto · Jul 31, 2011

Well, I'm going to return it... it's acting even weirder tonight, trying to put the iso on 6200 when I'm under a very bright light and iso 100 should be acceptable.. it is practically useless in Manual mode now.
It's also starting to make a very distinctive sound when I put it in manual. There is no sound when I put it into any other mode but when I switch it to manual, theres a weird whirr sound.

When it arrive, I noticed Amazon did not package it correctly. It came with 3 huge bubble inserts and only 2 of them were blown up, so there was room for sliding around. Maybe it was damaged then, I don't know.
I'm upset, I waited a month to make my purchase for my birthday and got 1 day shipping, and it's obviously defective

I tested my other lenses today again and all of them preform fine in manual mode.

Now I need to decide if I should get this lens again, or just pay the extra $150 for a canon.