Metering varies with lens

[JCDoss]

Group,


As a new D30 owner, I'm still trying to learn the ropes with my new stuff. I bought the D30, 28-135IS, and 50/1.4 to start off with. I'm experiencing some odd metering anomalies which I'd like to run past the group.

I'm finding that the 28-135IS photos taken in P mode tend to underexpose by about 2/3 to 1 stop, whereas the 50/1.4 looks about right. Even with the same shutter/aperture settings, there is a noticable difference in exposure.

Both photos can be found at:

http://home.bellsouth.net/personalpages/scripts/community.dll?ep=16&groupid=13268&ck=&ver=3.0

I know that metering on the bush would require at least a half-stop negative compensation, therefore the overall image *should* appear a little overexposed with both lenses. The 28-135IS photo looks well-exposed, except for the bush which is dark. The 50/1.4 is a little overexposed, but the bush looks pretty good (IMO).

Input?
JCDoss

[mrbobco]

hi jc...

keep in mind that that variable aperture on the 28-135 can come back and bite you sometimes (it really got on MY nerves and was one of the reasons to get rid of it and replace it with some "L" glass besides the obvious quality issue)

just a thought...

bob

[JCDoss]

mrbobco wrote:keep in mind that that variable aperture on the 28-135 can come back and bite you sometimes...

Hmmm... you think the reason it underexposes is due to the variable aperture? Maybe I should try a shorter focal length (to see if the switch from f/3.5 to f/5.6 has something to do with it).

Thanks for the idea,
JCDoss

[mrbobco]

hi jc...

i know that i had all assortment of exposure problems with the 28-135 when i first got my d-30...to show how clueless i was...i didn't realize at first just what was happening...all you have to remember is that your largest possible aperture (i.e. the lowest number) changes along with the focal length (i know it's obvious in the viewfinder display)...if all else fails...and you are using the flash...try using fel to meter the exposure first...and you should be fine...as i have suggested before...you can always try setting custom function #2 to setting #3 (uses fel for focus lock and half pressing the shutter button for exposure)

i did look at your pictures...and my personal preference is always to underexpose a little...you can recover details when underexposed but when they are grossly blown out...it can be pretty hopeless (although fred miranda does have a wonderful action that has helped me more than once) either way...i found the underexposed shot from the 28-135 more appealing to my eyes (it's all subjective i know : )

once i figured out how get the exposure a bit closer with the 28-135 i was happier...but haven't missed it since i bought the new lens (i do miss the light weight and longer focal length...but for all the beauty and clarity i gained with the L lens i won't whine : )

hope this helps...

bob

[JCDoss]

Hi Bob,

I realize that the overall exposure is better looking in the bush example taken with the 28-135 is that I metered only the bush with no compensation. Normally, I would have dialed in +2/3 or so. With the dark subject underexposed, the rest of the scene looks proper and probably more pleasing.

I posted another series taken indoors at:
http://www.pbase.com/jcdoss/exposure

Here, I used Av (f/5.0) for the 28-135 with IS off, with IS on, and with the 50/1.4. Again, partial center spot, ISO 800, metering off Blitzen's belly button. The metering circle just about exactly matched Blitzen's abdomen!

I think the 50/1.4 is spot-on. You can see that the 28-135 not only sorely underexposed in Av mode, but chose a faster shutter (1/25 vs 1/20). I then switched to M-mode with the 28-135 and dialed in the same settings as the 50 chose (f/5, 1/20) and STILL got an underexposure (about 1/2-2/3 stops IMO).

I wonder if there IS something wrong with the aperture diaphragm in the 28-135. I've inquired about an exchange... we'll see if unit #2 is any better.

JCDoss

PS: If the second 28-135 is as bad (or worse(!)), what would be your suggestion as an alternative for about the same price?

[mrbobco]

hi jason...

i'm going to guess that at iso 800 you weren't using the flash : )

funny...because those shots from the 50/1.4 do look so much better...i can't say for sure if there is something not quite right about your lens...i don't think i EVER got a usable shot without the flash with the 28-135 (but i'm hardly an expert) without the flash...they always tended to have some sort of exposure anomaly...in the beginning it was COMPLETELY operator error but as time went by and i understood the D-30 a little better i figured it out...the 28-135 still gave me a lot of unexpectedly strange exposures (operator errors aside) both indoors and outdoors (although it did much better for me outdoors)

you can check out a few pictures at the following link:

http://www.pbase.com/mrbobco/28135_photos

the funny thing is...i haven't looked at the pre 28-70L pictures i shot in a while...i DO see exactly what is happening to you on MY pictures too! it was why i found it necessary to use 1/3+ ev for the first month or two...until i started getting more natural light (or just more light in general) in my shots...in comparison to the 28-70L, these pictures look just a tad dark AND yellowish (at times) and of course...they're just not quite as crisp as the 28-70L, either...the galleries for the 28-70L are:

http://www.pbase.com/mrbobco/2870_l_gallery

please note: these are HARDLY artsy pictures (mostly of my daughter and cats)...but just some of my favorites...my work has not allowed me to travel much lately (outside of the late-night long exposure from my hotel balcony) so these are really for lens comparisons in the hands of average amateur...of course...comments are always welcome : )

you can make your own comparison, jason (in defense of the 28-135; i didn't know the camera quite as well, either...but then the pictures names go in a reverse sequential order of incompetence...nice feature from canon : )

as far as a suggestion for a comparable lens...i paid $425 for mine from B&H...i really DO suggest saving your pennies for a 28-70...as far as equivalents (pricewise) to the 28-135...i'll have to join you in begging for alternatives (although i didn't see any canon alternatives...although you can purchase a 70-200L/4.0 from b&h for $630) there may be some acceptable sigma or tokina alternatives but i'm bent on sticking with canon...in reference to returning the lens...i'm not sure on that one...personally i don't think you'll get better results than you've been having with a different 28-135...

thanks for listening...

hope this helps clarify...

bob

[JCDoss]

Bob,

That there's a big damn iguana! Looks like you're one of the few folks capable of raising an iguana to a normal adult size. (I'm a vet, and I'm well aware that iguanas are among the most difficult pets to care for.)

I don't see any distinct color cast with the 28-135... to me, the colors look similar. But to be honest, the exposure differences are so marked that I can't really get past that. In fact, I haven't really taken time to examine the benefits of IS because the exposure problems are so bothersome.

Anyway, I've decided to exchange my 28-135 for a new one. If the second unit is as bad as this one, I might just skip the range altogether and save the $440 for the 70-200IS or 100/Macro (I want both, but which should be *first*?). I'm not too keen on the 24-85, even though people rave about it. And I'm not too excited about an 85/1.8 if I'll have the 70-200/2.8 to cover that range.

Thanks for your advice. I'll keep you posted,
JCDoss

[mrbobco]

hi jc...

thanks for looking...although it really isn't all that related to this post...that iguana just happened to be sauntering through my backyard...he was MOST patient with me (i'm about 2 feet away from him most of the time) and was a rather willing subject...never want to lose a good photo op : ) i live in florida and you see them here all the time (i'm afraid people just get bored with them and let them out...it's common to see them glowing in the sunlight down by the canals)

i want that 100 macro too...but i think you'll have the most enjoyment out of the 70-200 first...i believe the the 70-200/2.8L will be the next lens i purchase too...although the IS version would be nice...i can't justify the extra $600 for it...

good luck with the newer 28-135...i'd be very curious to know if you see a difference...

bob

[JCDoss]

Hi Bob,

I think I'll probably opt for the 70-200IS before the 100/Macro, but I was surprised to see that the price for the 100/Macro was only $580. I thought it was closer to $700...

Anyway, since I filled out my warranty card, Canoga cannot accept a return. Therefore, I will have to deal with Canon warranty service. I've already sent off for the rebate... when the warranty card returns, I'm shipping my lens back to Canon. Hopefully, they'll straighten things out.

Meanwhile, I've still got my (amazing) 50/1.4... I really like that lens!

JCDoss

PS: Don't step on the iguanas!
PSS: I'll keep you posted... I'll update this thread as it happens.

[kalunde]

Hi

I have been using the 28 to 135 is lense for about two months and have no problem with exposure with or without flash. I have used the lense mostly in the P mode on the D30. After reading this post I ran a test by setting the camera to Manual mode and comparing the camera reading off a gray card to the reading of my accurate Spectra incident meter. Correlation was within 0.2 stops. I measured at 28mm and 135mm.

Kalunde

[JCDoss]

kalunde wrote:
Correlation was within 0.2 stops. I measured at 28mm and 135mm.

Did you compare your photos taken with the 28-135IS with those taken with another lens?
From what you're telling me, it sounds like my lens is definitely defective.

JCDoss

[kalunde]

I had no other lense to test at that time but after your message I took a few similar pictures with the my new Canon 50 f1.4 and got similar good exposures outdoors. With flash by the way my exposures frequently were way off until I discovered FEL.

Kalunde

[sasc]

I have this happen too. I also have an exposure difference between some shutter speeds with the 50mmf1.4. The focus seems sharper with close up shots. I still am not sure if my camera or my lens or both have a defect. My 50mmf1.4 isnt nearly as good as the 28-135

http:/pbase.com/sasc/tests

[nitwit3]

Get the Expo Disc and your problems will be solved...it isn't the lens. You need to learn about proper WB.
I had the same problems..don't anymore.
The 28-135 is very good in bright light and is difficult in dull to lower light.
The 50mm1.4 is great in available light.

Learn proper White Balance and settings.
LarryM

[JCDoss]

Hmmm... that's three recommendations for ExpoDisc.

The problem is... as I sit here tonight, I'm having trouble reproducing my results! Very bizarre... yesterday, I would dial in identical settings for both lenses, and marked underexposure for the 28-135. Today, same experiment, and the exposures vary by about 1/3 stop or less!

Something else... the 28-135IS minimum aperture switches from f/4 to f/4.5 right about at 50mm. I wonder if that had anything to do with it?

Finally, and this one is real, images I open in BreezeBrowser are SIGNIFICANTLY darker than the same image opened in PhotoShop. The difference in shadow detail is striking. And I'm talking about images I'm seeing on the computer for the first time (ie, no adjustments, no levels, no nothing!). What the heck is THIS about?

Bottom line... I'm beginning to think there's operator error at work here... but I can't figure out what I could be doing to lead to the results I had yesterday.

JCDoss

Edit: Discovery... Comparison of images at f/8, 1/x with both lenses yields very similar (and properly exposed) results. Comparison of images at f/4.5 or f/5.0, 1/x with both lenses yields marked underexposure of 28-135IS as compared to 50/1.4.

Edit #2: I added images to my gallery that demonstrate this change...
www.pbase.com/jcdoss/exposure

[sasc]

Im having more trouble with out of focus photos than with white balance. I can use EV and expose for highlights to take care of that.