Go Back   Steve's Digicams Forums > Digital SLR and Interchangeable Lens Cameras > Canon EOS dSLR

Reply
 
Thread Tools Search this Thread
Old Apr 14, 2005, 6:44 AM   #11
Senior Member
 
surfnron's Avatar
 
Join Date: Jun 2003
Posts: 578
Default

NHL,
Or anybody I guess. How do you read the charts?
Thanx,
Ron
surfnron is offline   Reply With Quote
Old Apr 14, 2005, 4:21 PM   #12
NHL
Senior Member
 
NHL's Avatar
 
Join Date: Jun 2002
Location: 39.18776, -77.311353333333
Posts: 11,547
Default

surfnron wrote:
Quote:
NHL,
Or anybody I guess. How do you read the charts?
Thanx,
Ron

FYI - http://www.luminous-landscape.com/tu...ding-mtf.shtml


The Canon's MTF are usually plotted as two set of curves with the upper ones (better - blue) when the lens is closed down to f/8, the lower ones are wide open: http://www.canon.com.hk/myContent/Pr...ow_to_read.htm

Sigma only plots the 2nd set of curve - ie when the lens is wide open: http://www.sigmaphoto.com/lenses/popup.asp

The way the lenses are measured are common however:

NHL is offline   Reply With Quote
Old Apr 19, 2005, 4:24 AM   #13
Member
 
Join Date: Jul 2002
Posts: 63
Default

If you are just starting out and have modest expectations of your pictures and dont plan on printing them above 5x7 or maybe 8x10 the this lens maybe ok for you.

I think you will find, however, that you will toss out more shots than you will keep. I have the Sigma 70-300 and I cant stand it. Its really soft at 300mm. Now, mind you, its far less expensive then lenses that produce better images.

If you can swing the higher price you might want to look at to Canon 70-300 f/4-5.6 IS.

http://www.bhphotovideo.com/bnh/cont...854&is=USA

The IS will will allow you to hand hold the camera and will potentially give you sharper pics.


Bilbo99 is offline   Reply With Quote
Old Apr 20, 2005, 7:53 PM   #14
NHL
Senior Member
 
NHL's Avatar
 
Join Date: Jun 2002
Location: 39.18776, -77.311353333333
Posts: 11,547
Default

Bilbo99 wrote:
Quote:
If you can swing the higher price you might want to look at to Canon 70-300 f/4-5.6 IS.

http://www.bhphotovideo.com/bnh/cont...=102854&is=USA

The IS will will allow you to hand hold the camera and will potentially give you sharper pics.
You may 'think' it'll give sharper picture - but not according to theses objective MTF charts:

70-300 f/4-5.6 IS: vs Sigma 70-300:


-> Technically it can NOT be sharper - more steady may be, but that's all!
Even close down to f/8 the Canon 70-300 IS USM is not as sharp as the Sigma wide opened @ 300mm :?
FYI - http://www.photozone.de/3Technology/mtf.htm
NHL is offline   Reply With Quote
Old Apr 20, 2005, 11:50 PM   #15
Senior Member
 
Join Date: Jan 2005
Posts: 301
Default

Hi NHL,

Definitely if the two MTF charts are comparable the Sigma is the superior lens (Canon thick black lines = Sigma red lines; Canon thin black lines = Sigma green lines). However, I also found this quote to be interesting from the Luminous Landscape article:

"Be aware though that different manufacturers have different measurement procedures, and therefore while comparing MTF charts between lenses in the same line is possible, and is in fact very useful in making a purchasing decision, doing so between different manufacturer's MTF charts isn't."

Yikes! There is no standardized test method??

So, you could be right ... the Sigma could be a much, muchsharper lens, and have better contrast reproduction... but then again, maybe not :-) However, from the pictures you posted it certainly appears to be a mighty fine piece of glass in the hands of a pretty good photographer, which is all that really matters.

Now, comparing the Canon MTF charts to ones for other Canon lenses, the $280 100-300 looks pretty average, especially against the charts for the 70-300 f/4.5-5.6 DO IS USM ($1150) or the100-400 f/4.5-5.6L IS USM ($1410). For the 'spensive lenses Canon uses the terms "superior performance" , "high performance" or "high picture quality" ... for the 100-300 they say "highly practical".

Taking all of the above into consideration,the $220 Sigma looks pretty good :lol:



Bob
BobA is offline   Reply With Quote
Old Apr 21, 2005, 7:45 AM   #16
NHL
Senior Member
 
NHL's Avatar
 
Join Date: Jun 2002
Location: 39.18776, -77.311353333333
Posts: 11,547
Default

BobA

You're absolutely right - some 'objective' data are better than no data, which is much better than 'subjective' internet reviewers who just say one lens is sharper and another is a dog with a sample of one!

The other thing that everyone seem to miss is the Canon MTF's data are not actually measured but computed from theoretical limits, ie the best they can be -> the lens that you buy is at most within this limit, as compared to other manufacturers especially the German optics which are actually derived from actual samples off the manufacturing lines... with the actual tolerances of the process factor in.
NHL is offline   Reply With Quote
Old May 4, 2005, 1:06 PM   #17
Senior Member
 
Join Date: Oct 2004
Posts: 182
Default

So is the Sigma 70-300mm a good lens or not?

I might be buying one really soon, I need to know!

-tlmiller10
tlmiller10 is offline   Reply With Quote
Old May 4, 2005, 1:31 PM   #18
NHL
Senior Member
 
NHL's Avatar
 
Join Date: Jun 2002
Location: 39.18776, -77.311353333333
Posts: 11,547
Default

tlmiller10 wrote:
Quote:
So is the Sigma 70-300mm a good lens or not?
For $200 it is - there's nothing close to it in the Canon line up except for the $1000 EF 70-300mm f/4.5-5.6 DO IS USM
FYI - http://www.photosig.com/go/photos/br...ing-d&id=23210
NHL is offline   Reply With Quote
Old May 4, 2005, 1:52 PM   #19
Senior Member
 
Join Date: Jul 2003
Posts: 3,396
Default

I agree with NHL,

in the Canon lineup you have the older 70-300 f4-f5.6 USMand 100-300 f4-f5.6 USM lenses that are cheep in the < 300$ range, and are rated as optically sub-standard glass.

Then there is the Sigma 70-300 (OK and inexpensive) and sigma 100-300 f4(excellent, but expensive) (and canon 70-300 f4-f5.6doIS USM, also goodbut overpriced about 2/3 of its cost is in the IS).

In the price range you are looking IMHO it is a good choice.

Peter.
PeterP is offline   Reply With Quote
Old May 4, 2005, 2:46 PM   #20
Senior Member
 
Join Date: Oct 2004
Posts: 182
Default

Well, I'm also looking at the Tokina 24-200mm 3.5-5.6 ATX lens as well. Would that be a better peice of glass than the Simga?

-tlmiller10

Thanks for the help guys!
tlmiller10 is offline   Reply With Quote
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 8:32 PM.