My big gun has arrived, how do I test it?

[Wickedfn4u]

Ok it got here! I have been lusting after a the Sigma 120-300 2.8 for 9 months now and I bit the bullet and just did it. I have heard (and mind you I have a 15-30 and 70-200 2.8 sigma and love them) that QC is an issue with the focus on 1D and 1Ds. I want to make sure all is right and different focal lengths and apertures. What would you do to test it and at what specs? Hope this makes sense or you can help me.

Cheers

Tom

[ron chappel]

Coincidentally one of the only problems i've heard of with a good modern sigma lens was with one of those.
The owner tested it against a brick wall (er,no not like that! :shock: :lol: )
and found the focus was different from one side to the other-it had decentered elements
If you do test it like that,be sure to have it at a perfect right angle to the wall

[Cadwell]

Go out and take lots of pictures with it! Congratulations on your purchase, I hope you enjoy it as much as I enjoy mine :D

[Scottes]

Just send it to me. I'll be happy to provide you with the results of my testing.

:)


I'd set it up an on tripod aimed at a brick wall or something similar. Min aperture, autofocus on the wall, and take a picture. Now flip the lens to manual focus, drag the tripod back a bit, and take a picture. Back a bit more, picture. And so on.

Do it again, except this time move the tripod forwards. Compare the pics, and judge the sharpest.

[Wickedfn4u]

I'd set it up an on tripod aimed at a brick wall or something similar. Min aperture, autofocus on the wall, and take a picture. Now flip the lens to manual focus, drag the tripod back a bit, and take a picture. Back a bit more, picture. And so on.

Do it again, except this time move the tripod forwards. Compare the pics, and judge the sharpest.

OK so by min aperture you mean 2.8 correct. This whole small number big opening has me SOOOO confused :roll: .

OK so I take one picture AF one MF Min Ap then move back and leave AP alone and do one AF MF again and so on. Then I walk forward doing the same? why would that change anything?

[Scottes]

OK so I take one picture AF one MF Min Ap then move back and leave AP alone and do one AF MF again and so on. Then I walk forward doing the same? why would that change anything?

You AF and take a picture, then switch to MF, move the camera, and take another picture. If the second picture is in focus it means that the initial auto-focus wasn't too accurate. The first picture, the AF one, should have accurate focus. Moving back and then forward tests with the AF is focusing too short or too far.

By using a large aperture like 2.8 you are minimizing depth of field, so out-of-focus stuff will be more apparent. If your depth of field was 10' then moving 1 foot back wouldn't show a difference in focus between two shots.

[robertwgross]

OK so by min aperture you mean 2.8 correct. This whole small number big opening has me SOOOO confused

Minimum aperture means maximum f-number. Maximum aperture means minimum f-number.

---Bob Gross---

[Scottes]

OK so by min aperture you mean 2.8 correct. This whole small number big opening has me SOOOO confused

Minimum aperture means maximum f-number. Maximum aperture means minimum f-number.

Darn! I did it again!

I *know* that max aperture is 2.8, yet I always communicate this backwards. Arrggghhh!

Thanks Bob. Once again I promise never to do this again....

[CyberDyneSystems]

I go out shooting with it and make sure that you images are focused ... that's about all I'd do. You've got at least a year to decide if it is working properly depending on your warranty (up to 4 years in the US)

[Wickedfn4u]

OK so by min aperture you mean 2.8 correct. This whole small number big opening has me SOOOO confused

Minimum aperture means maximum f-number. Maximum aperture means minimum f-number.

Darn! I did it again!

I *know* that max aperture is 2.8, yet I always communicate this backwards. Arrggghhh!

Thanks Bob. Once again I promise never to do this again....

Good I am not the only dolt with this max min thing. It is inverse I just have to remember.

[robertwgross]

Good I am not the only dolt with this max min thing. It is inverse I just have to remember.

There are several reciprocal relationships in photography. After a while, these will be burned into your brain.

Maximum aperture number means minimum aperture size.

Some people think of faster shutter speed as being "more shutter", but in fact it means less "shutter time".

The faster you go with shutter, the bigger the aperture size should be.

The longer the lens, the more you need a tripod.

The shorter the shutter time, the less you need a tripod.

The more expensive the lens, the more likely that you will drop it out of your vehicle and onto the ground.

The newer the Canon camera, the less readable the manual will be.

The more money you are being paid for wedding photography, the more likely that you will have major equipment failure.

---Bob Gross---

[Scottes]

Maximum aperture number means minimum aperture size.

Yeah, that's my out!

I said "min aperture" implying "min aperture number" but you thought I meant "min aperture size"...

Can I get away with this? If so, I'll change my sig back....
:wink:

[Wickedfn4u]

#6 is my fear after hearing about Tom turning his into a paperweight after having it roll out of the truck. That is why I did not buy a truck... wait I have one! DUH

[Wickedfn4u]

Ok it did just fine. I found a bird house in the neighbors back yard that was perfect. Bright red on a maple (nice bark grain) I tried it adding the 1.4 and 2x tc and also combined. Only problem I had was a couple of the pictures still had a bit of shake at 820mm but I was only shooting at 1/10 f8 guess I need a cable release.

Great god does it bring it right in.

[CyberDyneSystems]

Aaaawwww geez... a bit of shake at 820mm with dual T-cons... :(

Clearly defective.. You'll have to send it to me to evaluate :(




Pretty nice lens eh?

Have fun!

[Wickedfn4u]

My nine year old walked in and saw the camera sitting on my desk and say how come your camera is getting so fat. I don't think she was talking Phat too. I just smiled and and said all the better to see you with. Besides that is the new nick name for the gun

Phat the beast

[martcol]

I just smiled and and said all the better to see you with.

ROTFLMAO!

:lol: