Go Back   Steve's Digicams Forums > Digital SLR and Interchangeable Lens Cameras > Sony Alpha dSLR / Konica Minolta dSLR, Sony SLT

Reply
 
Thread Tools Search this Thread
Old Aug 16, 2005, 8:40 AM   #1
Junior Member
 
Join Date: Jul 2005
Posts: 15
Default

KM's 17-35 seems a bit expensive for such a short lens. Has anyone bought the Sigma 18-125? Is it a good alternative? What would be the drawbacks?

David
dollyp is offline   Reply With Quote
Sponsored Links
Old Aug 17, 2005, 12:41 AM   #2
Senior Member
 
bernabeu's Avatar
 
Join Date: Jan 2005
Posts: 990
Default

any zoom lens in excess of 2X is probably just a consumer grade 'junker'



you get what you pay for
bernabeu is offline   Reply With Quote
Old Aug 18, 2005, 7:55 PM   #3
Junior Member
 
Coolmax's Avatar
 
Join Date: Aug 2005
Posts: 20
Default

The KM 28-75 is about 3x and is not consumer junk. I don't know where that idea came from. Bad advice.
Coolmax is offline   Reply With Quote
Old Aug 24, 2005, 4:18 AM   #4
Junior Member
 
Join Date: Jul 2005
Posts: 15
Default

I'm trying to work out what is junk and what is not. In any case 28 at the wide end is not wide enough for a 'standard' zoom. I would have liked KM to have a lens covering around 18 to 50.

I'm asking what other lenses members of this forum have tried and what's good.
dollyp is offline   Reply With Quote
Old Aug 24, 2005, 8:47 AM   #5
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

Lens quality is always subjective, and a lot depends on the conditions you're going to use one in.

Most lenses are not going to be as sharp wide open. But, stopped down to f/8, the differences between them tends to narrow.

Anytime you put that much zoom range into a lens (i.e., 18-125mm), you're going to compromise quality to some extent. But, it depends on how you're using a lens and what your expectations are. Many users think this Sigma is a good value for the range. It's not that bright (f/3.5-5.6), and it's not going to be as sharp as some other lenses, but it's small, light and relatively inexpensive.

Konica-Minolta also has a new18-70mm f/3.5-5.6 lens that is showing up with the Maxxum 5D (this is it's kit lens). This lens will also be sold separately ($149 in the U.S.). At this price, I wouldn't expect superb quality. ;-) But, it is probably going to be comparable to the inexpensive Canon kit lenses.

You can see the press release including this lens here:

http://www.steves-digicams.com/pr/km...lenses_pr.html

Note that these new lenses are designed for Digital. They have a smaller image circle to make them smaller and lighter, so that can't be used on a 35mm SLR.

This also means that they won't work on any future "full frame" Digital SLR that KM introduces.

A good resource for evaluating lens sharpness is http://www.photodo.com/nav/prodindex.html

Their lens grades are based on MTF tests (which are not subjective) versus user opinions (as in many other sites). But, many newer lenses are missing.

Also see the lens performance surveys (based on users opinions) at http://www.photozone.de

Keep in mind that MTF tests alone don't tell you the whole story about a lens. So, look for opinions on things like Color, Contrast, Resistance to Flare, AF speed, etc. when comparing lenses. I'd also make sure to "test drive" some of the lenses you consider to see if you're comfortable with a lens' design.


JimC is offline   Reply With Quote
Old Aug 24, 2005, 9:38 AM   #6
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

P.S.

FWIW, I decided on the Tamron SP 20-40mm f/2.7-3.5 lens for my wide zoom (discontinued now, but still available). This one would be equivalent to a 30-60mm lens on a 35mm camera (after a 1.5x crop factor). Most of my photos are taken in this focal range.

I have not used this lens yet on a DSLR, but I got a good report from 7D owner that has it. He's had multiple wide zooms and says this one is the sharpest wide open (and I plan on using it that way). It also rates higher than any other wide zoom available in Minolta mount at photodo.com (and even tests better than the Minolta 20mm and 24mm f/2.8 primes). It's also a bit brighter than most wide zooms in this focal range (maintaining f/2.8 through 28mm, and only losing 1/2 stop to f/3.5 at 40mm). On the downside, it has a 6 blade aperture (if you care about that type of thing in a wide zoom).

User Surveys aren't as flattering for things like flare resistance with this lens. But, I'll see how it works on a KM DSLR when I get one (I don't own a KM DSLR yet).
JimC is offline   Reply With Quote
Old Aug 24, 2005, 8:07 PM   #7
Senior Member
 
bernabeu's Avatar
 
Join Date: Jan 2005
Posts: 990
Default

as i stated before:

2x is the max range for a QUALITY zoom lens
bernabeu is offline   Reply With Quote
Old Aug 24, 2005, 8:58 PM   #8
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

bernabeu wrote:
Quote:
as i stated before:

2x is the max range for a QUALITY zoom lens
LOL...

Well, I don't think you can make a blanket statement that 2x is the max, if you want it to apply to any lens in any focal range. Quality is subjective, too.

Some of the highest rated zoom lenses are greater than 2x zooms. Look at the MTF Tests for the Minolta 80-200mm f/2.8G, Canon 70-200mm f/2.8L, Canon 70-200mm f/4L, Sigma 70-200mm f/2.8 EX as examples.

Or, try this 28-85mm f/3.3-4 (3x). It tests better than any zoom made by Minolta:

http://www.photodo.com/prod/lens/det...28-8-160.shtml

It's probably more challenging to make a zoom with a longer range with high quality, but it can be done. I doubt optical engineering technology is standing still either.

How you define quality is another matter. Are you looking at resolving power alone, is barrel and pincushion distortion a big consideration, resistance to flare, are you using it in better light at smaller apertures, or do you need to use it wide open. Any lens is going to be a compromise to some extent (size, weight cost, flexbility, etc.).

So, a user will need to decide for themselves what's more important.


JimC 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 8:42 AM.