Go Back   Steve's Digicams Forums > Digicam Help > General Discussion

Reply
 
Thread Tools Search this Thread
Old Apr 25, 2008, 12:52 AM   #1
Junior Member
 
Join Date: Apr 2008
Posts: 14
Default

I've been a fan of Steves for a long time, but I don't know as much as I should about lenses. I'm hoping for some pointers or a reference to an article I can read.

Specifically, what is important about lenses if you want to take pictures of flat artwork? I find that if the subject is small I can zoom in with my Panasonic FZ7 to about halfway and it's all good. But if the subject is bigger, I have to pull the zoom all the way (sorry--what's it called when it's zoomed all the way out?) out, and then it does some barrelling.

Are there lenses out there specifically for doing flat work? What about for copywork like 11x14s that don't scan well? What do I need to be considering?

~Tim

PS. I did select "email me when a reply is posted," so I'm very eager to see any replies you post.
edtech2020 is offline   Reply With Quote
Sponsored Links
Old Apr 25, 2008, 11:29 AM   #2
Senior Member
 
Join Date: Dec 2006
Location: Davenport, IA
Posts: 2,093
Default

The solution you've found is generally the only solution available with zoom lenses. Most zoom lenses will zero out barrel/pincushion distortion at some middle range. You may, however be able to expand the range of subject sizes you can accommodate by using the macro focusing mode of your camera while still using a middle focal length. While I haven't specifically tested at that size I don't believe 11x14 would be any problem for my Kodak Z612. If I have a chance tonight or over the weekend I'll test and post.

The true solution, if it's worth it financially, is a DSLR with a prime macro lens. Among the design criteria for these lenses areflat field of focus and minimum barrel/pincushion distortion. If you are already using a DSLR then check the mfr's web site for suitable lenses. Third party lens mfrs such as Sigma also produce prime macro lenses.
ac.smith is offline   Reply With Quote
Old Apr 25, 2008, 12:06 PM   #3
Junior Member
 
Join Date: Apr 2008
Posts: 14
Default

"The true solution, if it's worth it financially, is a DSLR with a prime macro lens."

This is in my future then. For now I can stay in the middle range of my zoom and it's pretty much okay, but later I'll want a dSLR with a lens that advertises a flat field of focus.

Are such lenses ever available used? I'm scared that when I find out the prices for specialty lenses I'll have a heart attack, but maybe that's just because I don't know enough.

Is "prime macro lens" the term that I want to search for, like if I were aiming at a Nikon or Canon dSLR?

~Tim
edtech2020 is offline   Reply With Quote
Old Apr 25, 2008, 12:34 PM   #4
Senior Member
 
TCav's Avatar
 
Join Date: Sep 2005
Location: Washington, DC, Metro Area, Maryland
Posts: 13,571
Default

All zoom lenses (in fact, all lenses)have imperfections (to varying degrees) at their extremes. For what you need to do, you should stay away from the minimum and maximum focal lengths, the minimum and maximumapertures, and you should refrain from filling the frame with your subject.

Zoom lenses are not as sharp at their longest and shortest focal lengths as they are in the middle of their zoom range, and are prone to geometric distortion at the wide end. And all lenses are not as sharp at their maximum and minimum apertures, or at the edges and corners of the image as they are in the center. And they are not as bright at the corners (vignetting) as they are in the center.

Whatever camera you use, you should stick to the middle of the zoom range range, aperture range,and only use the middle 2/3 of the frame for the subject. That means that you should also have enough megapixels to crop and still have enough resolution to prevent pixelation in large prints.

You may be able to do all that with the camera you have, so you should try that first. But the Panasonic FZ-7 is only a 6 MP camera, and that may not be enough to get sharp images after cropping.

A dSLR with a good lens will probably do a better job than your FZ-7, but so might a number of less expensive P&S digicams.
TCav is offline   Reply With Quote
Old Apr 25, 2008, 2:43 PM   #5
Senior Member
 
Join Date: Dec 2006
Location: Davenport, IA
Posts: 2,093
Default

edtech2020 wrote:
Quote:
Are such lenses ever available used? I'm scared that when I find out the prices for specialty lenses I'll have a heart attack, but maybe that's just because I don't know enough.

Is "prime macro lens" the term that I want to search for, like if I were aiming at a Nikon or Canon dSLR?

~Tim
The terminology "prime" means single focal length or "NOT ZOOM". Olympus, Canon, Nikon, Sony, Pentax and Sigma in the lens section of their web pages have asub-group called Macro. These will all be single focal length (prime) lenses. Any DSLR from the mfrs above (and sorry if I left out someone) and one of their purpose built macro lenses will greatly exceed the performance of your FZ7 or my Z612. Sigma also makes purpose built macro lenses that are useable on most of the bodies above.

Expect the new prices to range from expensive to heart stopping but even the least expensive will exceed the performance of your current camera. I don't really keep up with the used DSLR/lens market. TCav might have current information or give you research clues.
ac.smith is offline   Reply With Quote
Old Apr 25, 2008, 3:51 PM   #6
Senior Member
 
TCav's Avatar
 
Join Date: Sep 2005
Location: Washington, DC, Metro Area, Maryland
Posts: 13,571
Default

ac.smith wrote:
Quote:
Expect the new prices to range from expensive to heart stopping but even the least expensive will exceed the performance of your current camera. I don't really keep up with the used DSLR/lens market. TCav might have current information or give you research clues.
I don't really think you need a macro lens. As I said in my first post, you shouldn't actually fill the frame with your subject. You should avoid having any part of your subject close to the edges or corners of the frame to avoid geometric distortion, vignetting and loss of sharpness. That means you won't actually need to get very close to your subject. Maybe as close as 1 meter, maybe less depending on the subject. That's not macro.

But a good macro lens will run about $400 new, and about $200 used if you're lucky.
TCav is offline   Reply With Quote
Old Apr 25, 2008, 10:47 PM   #7
Senior Member
 
VTphotog's Avatar
 
Join Date: Mar 2005
Location: Extreme Northeastern Vermont, USA
Posts: 4,229
Default

While the ideal solution is a camera/lens without barrel or pincushion distortion, there is a workaround in post-processing. there are Photoshop plugins available for just this sort of correction. My Photoimpact has it as part of the program. The free RAW converter (which will also work with other image formats), Raw Therapee has lens correction as well.

brian
VTphotog is offline   Reply With Quote
Old Apr 25, 2008, 11:25 PM   #8
Senior Member
 
Join Date: Dec 2006
Location: Davenport, IA
Posts: 2,093
Default

TCav wrote:
Quote:
I don't really think you need a macro lens. ...That's not macro.

But a good macro lens will run about $400 new, and about $200 used if you're lucky.
Now having copied some 11x14s I agree unless he is doing this for archival or art print purposes. I am posting three 11x14 and one 8x10 copies. These are 35 year old prints that have crossed the Atlantic four times and often storedunder less than archival conditions. I shot these copies at focal lengths between 105mm and 143mm equiv. in both macro and normal focus (this lens has a range of 35-420mm) and had no problem with distances in my rather small (8x10 feet) computer room. A suitable light set might well be more important than a high end macro lens. You can see the inadequacies of my impromptu light set-up.

EXIF data is intact.

Attached Images
 
ac.smith is offline   Reply With Quote
Old Apr 25, 2008, 11:27 PM   #9
Senior Member
 
Join Date: Dec 2006
Location: Davenport, IA
Posts: 2,093
Default

Another 11x14.
Attached Images
 
ac.smith is offline   Reply With Quote
Old Apr 25, 2008, 11:28 PM   #10
Senior Member
 
Join Date: Dec 2006
Location: Davenport, IA
Posts: 2,093
Default

Straight lines in an 11x14.
Attached Images
 
ac.smith 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 6:44 PM.