othursdayz

I have a question regarding sensors and diffraction. I searched the forums and

online and couldn't find a straight forward answer.

 

I understand diffraction and its effects on an image at different aperatures. I

was wondering, Canon just released the XTi which has a 1.6X crop factor and is

10.1 megapixels, the Canon 30d is also a 1.6X sensor but is 8.2mp, so both

cameras have identical sensor sizes, but the pixels are smaller on the XTi

right? So how would that effect diffraction? Will pictures be sharper at

smaller aperatures when there are more pixels on the sensor or would the

opposite be true?

 

As always, any help/incite would be appreciated.

 

Thanks in advance.

Interesting, I've never heard of hot pixels, thanks for the heads up. I had the custom function noise reduction setting on in all of the pictures that they have been showing up, I have it set to AUTO, so it does it when the camera thinks it needs to, but the camera definitly preformed the noise reduction even on the ones where the same pixels showed up.

I know that sometimes with LCD's and monitors, pixels can just die, is that

possible for DSLR sensors? I've noticed with some of the bulb shots of the sky

that there are a few scattered pixels that are just solid red and blue. Its not

my monitor becuase if i move the photo around on the screen they're still in the

same spot on the photo. I took a bulb shot with the lens cap on to see the

results and there are a few that consistantly keep showing up, my guess is that

the pixels on the sensor are dead since these same spots are in a few pictures?

Or is it noise? Any thoughts, experiences, ideas, suggestions?

 

Attached in the bulb shot.

Thank you all for the responses. I was convinced there was something wrong with my lens and I brought it back to the store and they exchanged it for me. I got the new one home and it was a big difference. It might have been because I was more optomistic about the fact that statisticly I was less likely to get ANOTHER bad one (if the first one was really bad in the first place). But i reshot some of the same pictures and there is definitly a difference in quality. After using the new lens for a few days I am really impressed with it, and very happy for getting it.

 

So thanks again everyone for you input and your help, I'm a happy camper.

Not wide enough for me with the 1.6X factor.

 

 

Does anyone have this lens (Sigma 10-20) that can compare some of their shots to mine?

Ryan,

I did what you suggested and I did infact get slightly better results, but still decent and not what I expected. I guess it does need to be rechipped, but I guess there is still a problem with the optics, which I hear is quite common with Sigma lenses.

Ryan, The tree was in focus. I did the same shot a number of times with manual and automatic focus. Thanks for checking them out.

the other photo<div></div>

I was all set to buy the Canon EF-S 10-22 but when I tested it out in the store

(B&H) and then tried the Sigma 10-20, the Sigma just felt better, and so did the

price. I checked out the reviews on

http://photozone.de/8Reviews/lenses/sigma_1020_456/index.htm

and image quality between the two are very close and high. So I bought the

Sigma 10-20 and have been unsatisifed with the images that it has been

producing, nothing seems very sharp. I don't know if I have too high of

expectations, or I've heard to many stories about Sigma's QC, or this is

ACTUALLY something wrong with the lens I own. I've taken shots at a variety of

apertures and nothing seems to be impressive at all. I've uploaded two

pictures, the only two pictures in my portfolio or gallery on here, they're 100%

crops, unedited; I just was wondering if anyone with the same lens and 20d or

30d could check them out and see if theres something wrong here. I would

greatly appreciate it.

 

The one of the tree dead center, is a dead center 100% crop @ wide open. The

2nd picture with the water and rocks are at f/9 or 10.

 

Any input of help would be appreciated.<div></div>

Just got my 30d and it started saving shots in the same directory.

Just won a new Canon EF-S 10-22 lens from an authorized Canon dealer on eBay and

I was offered an extended warrenty for it for 3 years, for 65 dollars or so,

through a company Square Trade. I've heard the name before, but never anything

about it. Just curious to see if anyone has an experience dealing with them. I

don't think 65 dollars is unreasonalble price unless this company isn't very good.

 

This is their website;

 

http://www.squaretrade.com/buyersvcs/processWarrantyEntry.do?ccode=bs_war_direct

Alright I got it. Sounds good. Thank you all for your help. I was just seeing if there was anyway to make myself feel better about buying my 3rd ef-s lense (today) 10-22, and seeing if there was ANY possible way for them to be used on a future FF camera, hopefully the 5D someday :). Thanks again everyone.

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If the 60mm ef-s could be used on full frame cameras with the use of extension tubes, would it be possible to use all of the other ef-s lenses on full frame cameras by doing the same thing?

I searched on here and online to find if the Canon EF25 II extension tube is

compatible with the ef-s 60mm but could not find an answer.

 

I just upgraded my dead 20d to the 30d and own the ef-s 60mm. If the ef-s 60mm

lens can mount to the Canon EF25 II; and the Canon EF25 II can mount to a full

frame camera like the 5d, is that a way to use the ef-s 60mm with a full frame

camera?

 

Anyone have an experience with Canon EF25 II?

 

Does the extension tube allow me to achieve the same magnification with the lens

further or away, or would I have to move closer?

 

Any help would be appreciated. Thanks!