PDA

View Full Version : is there a problem with my lens or camera?




lewys
Jun 4, 2011, 05:21 PM
Hi guys. First of all sorry for the long post

I own a d90 and a few weeks ago i bought a sigma 70-200 2.8 mkII but it was front focusing by around 20mm so i took it back and got my money back as they didnt have another one (they have been discontinued).

A few days ago i got another one and the first thing i done was focus on someones eye to see if it had a focusing problem like my others and after looking at it it seemed really soft and looked like it focused more on the eyebrow.

I have taken some more test shots here (http://www.flickr.com/photos/63399877@N05/) so you can have a look and see what you think.

First one is a test chart
In the paper pic i focused on the word ' suspects'
In the pebble shot i focused on the twig in with the pebbles
In the two flower shots in the first one i focused on the stem leaf behind the flower and in the second i focused on the actual flower
On the light shot i focused on the top of the light

It seems like this lens is also front focusing like the last sigma 70-200 i took back for it.
I bought a tamron 28-75 a few weeks ago and took that back due to front focusing and when i tried a sigma 20something-70 in the store it didnt seem to sharp around the eyes when i took a portrait of my girlfriend so i didnt bother buying it.

My nikon 50 1.8 and my tamron 90mm dont seem to be front focusing (if they are it is by hardly anything and i cant really notice it) and i really cant tell if my tamron 10-24mm is as its hard for me to see on a wide angle

Could it be that there is a problem with my d90? i dont have another body to try so i cant really test.

if it is my body would it be wise to trade in my d90 for a second hand d300 body or is the d90 better? i dont use the video function on the d90 much



jabbott
Jun 4, 2011, 09:24 PM
It does look like it's consistently front focusing, and the fact that the other Sigma 70-200 II did the same thing makes me inclined to think it is the lens. That said, my experience with Sigma and Nikon is limited at best.

Bryan Carnathan at the-digital-picture.com (http://www.the-digital-picture.com/) has said that two out of three copies of the Sigma 70-200 II that he's tried have had severe front focusing issues. The other one had a foreign object inside the lens. Here (http://www.the-digital-picture.com/Reviews/Sigma-70-200mm-f-2.8-DG-HSM-II-Macro-Lens-Review.aspx) is his review if it helps.

lewys
Jun 5, 2011, 02:20 PM
if it is a camera body problem would all the lenses front focus or just some of them? i ask this because i think my 50mm 1.8 and tamron is fine (tamron may be slightly off) but i have also tried two other different lenses in store and they both seemed soft so maybe they were also front focusing.

the lens i tried in store was tamron 28-75 2.8 and sigma 17-50 2.8

jabbott
Jun 5, 2011, 04:43 PM
I don't know for sure, although I would be inclined to think it wasn't the camera based on what you've said. Anyone else have any thoughts about it?