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

Reply
 
Thread Tools Search this Thread
Old May 21, 2005, 5:46 PM   #21
Senior Member
 
Join Date: Feb 2005
Posts: 175
Default

peripatetic wrote:
Quote:
ChrisDM wrote:
Quote:
But, if you are used to getting very sharp images, as I was with my Minolta A200, you will want to invest in a very good lens. The kit lens, and other inexpensive lenses, generally produce "soft" images which require sharpening during post-processing. What I have discovered quickly about lenses, which is true with just about anything else: You get what you pay for. Don't waste a $1000 camera with a $99 lens.
DSLRs produce "softer" images because that is what they are designed to do. It is mostly a function of the degree of anti-moire filter that is placed in front of the sensor. Generally the more expensive the camera the more the manufacturer errs on the side of extra filter at the expense of in camera sharpening.

When you say "used to getting very sharp images" I can't help wondering exactly what you mean. Do you mean at 240ppi on a print? Or at 300ppi on a print? How large is your print and at what distance are you viewing it? Or are you judging it at 100% magnification under photoshop (which by the way is essentially irrelevant)? Or at 800x600 resolution on an image resized for web display?

The point is that sharpness is different for each of these output types. Something that is optimally sharpened for 100% viewing in Photoshop is completely artificial, it only matters for pixel-peeping and actually degrades the quality of the print.

Once you have added too much sharpening, or indeed even sharpening of the wrong kind and you use the image for another purpose you are degrading that image quality, artifacts can appear in the image and, like moire, once the artifacts exist they are essentially impossible to get rid of. You can add more sharpening but you can't take it away.

You might find this article interesting:

http://www.luminous-landscape.com/tu...harpness.shtml

And finally, all of the kit lenses on the Rebels and 20D are quite capable of producing very sharp results if the photographer knows what he or she is about. The MTF charts for those lenses make it perfectly clear that this is the case, if one can't get sharp pictures from those lenses it's not usually the fault of the equipment.
True, but in order to get sharper pictures with the kit lens, or many other inexpensive lenses, you must "stop them down"... I had a Minolta A200 that produced very sharp images no matter what aperture I had set. I never had to think, "I'd like to shoot this at f2.8, but I'd like the focus point sharp also so I'd better stop it down..."

What's the point of buying a lens capable of shooting at wide apertures if the images aren't acceptable (to me) at certain apertures? Now that I've learned the limitations of these lenses, I buy quality (and generally more expensive) lenses that are capable of producing beautiful images throughout their range.

Also, the ability to view and crop an image to a high degree, even 100% is not irrelevant, say when you are far away fom your subject and don't have a long enough lens.

And true, there are exceptions to the "you get what you pay for" rule, and the Tamron 28-75 is certainly one of them. But generally, it is a valid starting guideline when shopping for lenses or anything else mechanical or electronic.
ChrisDM is offline   Reply With Quote
Old May 22, 2005, 5:29 AM   #22
Super Moderator
 
peripatetic's Avatar
 
Join Date: Nov 2004
Posts: 3,599
Default

ChrisDM wrote:
Quote:
True, but in order to get sharper pictures with the kit lens, or many other inexpensive lenses, you must "stop them down"... I had a Minolta A200 that produced very sharp images no matter what aperture I had set. I never had to think, "I'd like to shoot this at f2.8, but I'd like the focus point sharp also so I'd better stop it down..."
Fair enough, and I don't say that this applies to you, but MOST people upgrading from P&S to DSLR when they complain of this are really experiencing DOF issues. The DOF on a P&S at the same camera settings is much deeper than on a DSLR that they think the picture is soft when its not. It's just that some of it is out of DOF.

Quote:
What's the point of buying a lens capable of shooting at wide apertures if the images aren't acceptable (to me) at certain apertures? Now that I've learned the limitations of these lenses, I buy quality (and generally more expensive) lenses that are capable of producing beautiful images throughout their range.
Quite right, if your standards are such that you need pro lenses to get what you want then you have no choice but to fork out the cash. However, when people say that the 17-40 L is much sharper than the 17-85 or even the 18-55 they're simply talking rubbish. Looking at the MTF charts proves the point.

Quote:
Also, the ability to view and crop an image to a high degree, even 100% is not irrelevant, say when you are far away fom your subject and don't have a long enough lens.
No, but when cropping significantly your lenses need to be much higher resolution. So berating a lens for its sharpness when you're using it outside its design parameters is hardly fair.

In the interest of completeness it would be very interesting to know what your criteria are for sharp prints : ppi, print size and viewing distance.

I recently attended the Lee Miller exhibition at the National Portrait Gallery, although she shot on MF format film, none of the pictures on display was printed at larger than about 8"x8" and viewing distances in a gallery are usually about 3-6 feet. A rebel or 20D has more than enough resolution to print exhibition quality prints at that size. even with the EF-S 18-55mm.

For my needs the 20D plus 17-85mm is more than good enough, my prints are either 4x6", 5x7", or A4, viewing distances on A4 are usually 3 feet or so. That lens plus camera give more than sufficient resolution for these parameters, sharpness is simply not an issue.
peripatetic is offline   Reply With Quote
Old May 22, 2005, 2:17 PM   #23
Senior Member
 
Join Date: Feb 2005
Posts: 175
Default

peripatetic - I appreciate your insights and opinions...

I will usually print my favorie shots at 8x10 inches (A4 I believe). However, I do "pixel peep" to analyze the quality of my lenses. I guess I was originally frustrated when I traded a $600 camera (Minolta A200) for a $1000 camera and got seemingly less impressive images when viewed at full size. (Even though I realize that these differences would be imperceptible to othes viewing my prints).

So, there began my learning curve, and it will hopefully continue for a long time to come...

ChrisDM is offline   Reply With Quote
Old May 22, 2005, 3:28 PM   #24
Super Moderator
 
peripatetic's Avatar
 
Join Date: Nov 2004
Posts: 3,599
Default

Chris,

Have a look at this site:

http://www.pixelgenius.com/sharpener/

I'm not sure if you use CS or Elements, but if you're using CS then this software is really worth investigating.

It divides the sharpening into 3 stages: capture, creative and output.

In the digital age we do spend a lot of time producing web output for forums and websites and so on. And there's nothing at all wrong with that, but do keep in mind that you want to sharpen appropriately. If you get a pin-sharp 1024x768 who cares what it looks like at 3500x2500? If you're printing 8x10 - who cares what it might look like under a loupe at 16x20?

Here's the thing - can you get great results at the actual output you use? Concentrate on getting the best you can for an 8x10 print and a 1024x768 web graphic. You may be surprised to find that it's actually possible that even without any sharpening your Rebel/20D can give a better looking print than the Minolta under some conditions - this might occur because the in-camera sharpening on the A200 will actually over-sharpen and leave halos or other artifacts that you can see in an 8x10, but they won't be there in the print from the Canon.

I think you will also find that different subjects want different sharpening techniques applied. When you're trying to bring out the detail of feathers on that seagull shot then you'll sharpen like crazy looking for the "wow" factor. But when it's a photo of you wife and you sharpen to the point of being able to see the pores on her skin it won't be a "wow" it'll be a "yuck" and she'll not be thanking you for it. Try un-sharpening a tight portrait on the A200 without leaving behind artifacts that affect the print.

I'm not dis'in the A200 here - 'cos I'm sure that most of the time it does a great job. But there will be times down the road where you'll think: "Now here's a shot I could never have got with the A200".

Some old pros have collections of lenses which they will use in different circumstances. "This old Zeiss 24mm doesn't have the resolution of a modern lens, but it gives a great contrast and beautiful colour rendition for sunsets." Who cares how sharp a picture of cloud and water and hazy mountains is? I guess there's no need to keep flogging this horse. :-)

So that's my advice - concentrate on your output for a while. Then when you start to run into limitations with your equipment you may just find yourself looking for different things rather than whether it looks sharp at 100% in PS. You might find that you're starting to notice CA or vignetting problems or barrel distortion or it's got condensation inside or the zoom action is loose and you've only had it for a year - or whatever. You may still be an L-glass junkie, but it'll be for the right reasons. :-)

peripatetic 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 6:18 AM.