50d + Sigma 150 + kenko x2 TC problem

[Nikon Kid]

50d + Sigma 150 + kenko x2 TC problem

If I shoot M Tv Av I need to close down 2 stops exposure level to get the correct exposure, but when I change over to Full Auto its a perfect image

[Roy C]

50d + Sigma 150 + kenko x2 TC problem

If I shoot M Tv Av I need to close down 2 stops exposure level to get the correct exposure, but when I change over to Full Auto its a perfect image
What do you mean Terry - you have to dial in EV-2 to get the correct exposure?
With TTL metering that's strange.

[postcardcv]

What do you mean Terry - you have to dial in EV-2 to get the correct exposure?
With TTL metering that's strange.

It's strange but not unknown, I've heard of people having a similar problem when using the Kenko 1.4x on long lenses. It's a metering issue, a bit of a hassle but easy enough to compensate for it.

[Nikon Kid]

I am going to check my 1.4 tc on Sigma and then check my 400mm with both and see if thats the same, yes Roy I have too compensate by =2 EV.......

To tell you the truth I cant remember a problem when using a 1.4 with the 400mm I will do some more tests to-morrow

[Roy C]

To tell you the truth I cant remember a problem when using a 1.4 with the 400mm I will do some more tests to-morrow
I have never had a problem like this and I have a Kenko 1.4 tc canon 1.4tc and a teleplus (Kenko) 2xtc. I have used the tc's even stacked on at least three of my lenses and never had a metering problem (tried all three on my 400/5.6 once :-O )

p.s. mind you if it happens all the time, then like Pete say's its no real hassle to dial in the - ev

[paul goode]

My sigma 500mm f4.5 underexposed by about 1 1/2 stops when used with a kenko tc. One of the downsides of using 3rd party kit but easy enough to fix, so long as you remember.

[Roy C]

I wonder if this is just a problem with Sigma lenses and Kenko tc's.
I still find it strange that this could happen with TTL metering - I thought that you could stick anything between or at the end of a lens and the metering would be correct because the camera meters from what it can see through the lens - obviously not :h?:

[Nikon Kid]

I went and tested all my lenses with the 1.4x 2x kenko this seems to be a intermittent problem I was on evaluative metering at the time, so I changed over to spot did some test all OK went back to evaluative metering and its OK the correct exposure. I also went through changing the metering and all are OK now. I can only assume its the camera playing up, I cleaned the contacts with a micro cloth and see how we get on in the future.

[Nikon Kid]

I was messing about in the Garden and thought I would take a pic of my resident Dove,
I used the 400mm f5.6 + kenko 2x handheld not cropped at all. I thought it came out acceptable what do you think.

[Vectis Birder]

Pretty good, Terry. The sharpness looks good enough.

[Roy C]

I was messing about in the Garden and thought I would take a pic of my resident Dove,
I used the 400mm f5.6 + kenko 2x handheld not cropped at all. I thought it came out acceptable what do you think.
That's very good Terry, especially for hand held. The 400/5.6 takes tc's very well, here is one I took a couple of weeks ago with a 17 year old teleplus 2xtc and the 400/5.6.

[Nikon Kid]

That's very good Terry, especially for hand held. The 400/5.6 takes tc's very well, here is one I took a couple of weeks ago with a 17 year old teleplus 2xtc and the 400/5.6.


Like yours Roy, tapped pins I see by your exif............

I just might get out and about with my new 800mm :-O I need to find some birds.........

[Roy C]

Like yours Roy, tapped pins I see by your exif............
Not taped pins Terry, the old teleplus that I have has only got 8 pins so non reporting.

Trouble with using a 2x tc in the field is that you have to get fairly near the bird to get good detail which defeats the object of using it in the first place IMO. I have used it on the estuary for waders that are 30 metres or more away (with tripod) and have always been disappointed with the results.

[Nikon Kid]

Not taped pins Terry, the old teleplus that I have has only got 8 pins so non reporting.

Trouble with using a 2x tc in the field is that you have to get fairly near the bird to get good detail which defeats the object of using it in the first place IMO. I have used it on the estuary for waders that are 30 metres or more away (with tripod) and have always been disappointed with the results.


Thanks Roy wrong again, I might go out to-day before it rains and try and get some shots of birds with 400mm + 2x tc, with my 15mp on the 50d cropping might be a bit better than the 40d.

[Roy C]

Thanks Roy wrong again, I might go out to-day before it rains and try and get some shots of birds with 400mm + 2x tc, with my 15mp on the 50d cropping might be a bit better than the 40d.
With a 2x tc on board Terry that should be a reason to crop less and not more I would have thought ;););)

Mind you when it comes to IQ one man's meat is another man's poison.

[Nikon Kid]

Got this one to-day 400mm x 2TC kenko cropped

[pecrow]

well, to add to the debate, i use a 30d and have a kenko 1.5x tc. i find that adding the kenko to any of my ef lenses, it throws the metering out. net result is a 1 stop overexposure. this is easily compensated for but i'd love to know why this happens. surely the camera responds to the light entering with an exposure setting and if anything, a tc ought not to cause over/underexposure... even if the camera doesnt know its there.

there is a LONG tc thread over on "photography on the net" but most of these are concerned with focus issues. nobody seems to have posted about exposure problems.