To sharpen or not to sharpen?


posted on 20th of february, 2009

When I first started with digital photography around three years ago it was with a pretty decent compact, a Canon A95. For the first year and a bit I sharpened every single of my images by a factor of 150% & pixels at 3-4 ignore threshold and 3-4 radius, sometimes more in addition to boosting the contrast and brightness by 40/30 or more..

The resulting images looked great on my monitor and didn't turn out too shabby on 8x10 prints either, while for web they were ideal... However.... when I started looking at selling my images via microstock I got a whole lot of rejections (over 90%) due to over sharpening and over filtering. Only the best images made it through and even those I would never submit now days.

Thus the learning process commenced.....

What I learnt is that by using the unsharp mask to heavily you introduce artifacts or not so much as introduce but accentuate. Therefore the lower the quality of the digital sensor on your camera and the quality of the lens used, the higher the number of artifacts in any given image. The only way to ever examine the quality of an image is at a 100% 1/1 ratio and using a proper image editing software such as photoshop. It is a fine balancing act and even nowadays I still get an occasional rejection due to over-sharpening or artifacts. This is also because a lot of my images are HDR where you sandwich several different exposures into one, a process which if you like triples or doubles the number of artifacts that you end up with. However I still submit my HDR's to microstock and have a pretty high acceptance ratio at most agencies.

Its also worth noting that all digital cameras nowadays already do some degree of software driven sharpening at the capture stage inside your camera. Therefore it is important to understand just how much your camera does before you put the image on the editing table. The key thing is to keep in mind is your final intent for the image edited.

If you want to use your images for the web and are not fussed about going larger then an 8x10 print or selling your shots then you can quite easily go up to 150% & pixels at 3-4 ignore threshold and 3-4 radius, providing this holds up to a brief visual inspection at 100% ratio. If however you wish to leave the possibility of doing larger prints or selling your work then a number of factors need to be carefully considered:

1 - The quality of the lenses that you use (more on this below).

2 - The quality of the camera's sensor (more megapixels doesn't equate to better sensor nor better images, find out about your camera from http://www.dpreview.com/ ).

3 - Stability or the dreaded camera shake. Don't use a shutter speed lower then the focal length that you are shooting at and if you do make sure you have invested in a very robust tripod or have faith in your IS or image stabilization on either lens or camera.



It is for this reason that I only ever use the best lenses possible in terms of quality, reading carefully all lens reviews and buyer feedback( bookmark this site http://www.fredmiranda.com/reviews/ ) and making an informed decision before each and every single purchase, be it $100 or a $2000 lens. I have bought lenses before for around the 1k mark only to find out the quality of the final result was sub-par and below my expectations, rendering those useless to me. Luckily I managed to sell these on E-bay with minimal if any financial loss, hoping that the buyers would be satisfied with the quality they got for their own needs. I also make sure that I use a camera with a good quality sensor, or as good as I can justify and afford, but never at the price that would force me to compromise on any of my lenses budget wise.

A standard prime (non zoom) lens will almost always produce a superior results to a zoom lens. I know this as I have conducted many tests in controlled conditions over a variety of lenses. Not to say that all zooms are bad, there are some that really stand out like the Canon's 70-200mm L (any of the four available F2.8IS, F2.8, F4 and F4IS respectively) series. The quality of the images produced by these lenses is quite simply outstanding for a zoom. Canon have really nailed it with this one in terms of optical alignment and calibration.

Off the lens mantra and back on topic, indicatively speaking and from my own experience I now never sharpen by a factor higher then 55% & pixels at 0 ignore threshold and 1.5 radius. This is unless of course I'm making an avatar or a web only image in which case I might go as high as four times that. I also do not use the unsharp mask unless I really feel it is absolutely necessary, for instance when I might be trying to compensate for lower focus, lower depth of field or even the occasional camera shake. I only ever do this if I really need the image. Furthermore I hardly ever sharpen images with any visible noise, ie low light or HDR's. Thus my final advice is to know your equipment, shoot wisely and always inspect the final image at the editing stage at 100% ratio, corner to corner before you save and index. Have fun and I hope this helps

Comments (12)

Comment by Drizzle on March 16, 2009

Great post, I think you've got to judge each pic on its merits though, setup/conditions etc.

Creative Agency Manchester

Comment by Tipareth on March 07, 2009

I've quicklly realised the perils of sharpening myself. I use sharppening only with layer mask, so I can control it, and apply it only where is necesarry, especially on edges, avoiding large surfaces. Also I never use sharpening above 1.8 radius.
If the photo got bit of noise I avoid sharpening, Instead I apply an 50% gray layer and work with burn and dodge, painting on edges, and trying to do manually exactelly what a sharpening filter does. It's harder, but absolutelly harmelss for the photo, and got also many advantages, you can also apply wonderful reflections, and shadows...

Comment by Krystof on February 21, 2009

Thank you everyone, I'm glad my notes can be off some help to some of you. Also Josh the lenses that most disappointed me was my 100-300 mm F5.6 IS Canon EF that cost over 1k and produced very soft results with purple fringing and other artifacting... Also was never that impressed with my 400mm L Canon F5.6 despite it's 2k price tag.

Comment by Dersankt on February 21, 2009

I never sharpened my pictures. I always made them 1-2mp smaller if noise seemed too obvious...

Comment by Petroruth on February 21, 2009

Good article it is great that dream photographers are so willing to share their knowledge . It sure helps us rookies.

Comment by Joshuaraineyphotography on February 21, 2009

Thanks for the info Christopher. I would love to know what lenses you have purchased that didn't meet your microstock needs. Also, I have posted a sharpness tutorial on my blog that might be helpful to you and to other microstock photographers. I use a method of sharpening that gives you a bit more control when shooting for microstock. It lets you sharpen detail and edges without adding to noise or artifacting. Try it out sometime and I think you'll like it a lot more than sharpening in RAW or using an unsharp mask.

Sharpness Tutorial

Comment by Chrisrawlins on February 20, 2009

Hi Christopher

Thanks, a very useful read.

I've only just notice the difference btw zoom and fix lens. I don't know why it's taken me so long as the difference is huge. Now my 50mm is always packed with my camera gear.

Comment by Bradcalkins on February 20, 2009

I think from a stock photo perspective you want to keep sharpening to a minimum - especially for out of camera JPGs. With RAW files I think a little is necessary most of the time. Most workflow suggestions I've read leave sharpening to the last step as it is dependent on the size of the output (paper, screen, etc.) - I assume that buyers here would want to do their own sharpening for that reason. I'd be interested to know if buyers prefer minimal sharpening... As for the 0 threshold and noise in the photo - setting a small threshold value should help avoid sharpening the noise in some pictures.

Comment by Retina2020 on February 20, 2009

Useful article. Thanks. It's inherent on the camera sensor to have a bit of blur even with the sharpest lenses since there is an anti-alias effect by the sensor pixels thus creating blur. I tend to use high-pass sharpening techniques over USM to give better results and have a bit more flexibility in noise control.

Comment by Creativei on February 20, 2009

Worth the time spent reading this blog, very useful.

Comment by Aughty on February 20, 2009

Well worth the read. Thank you.

Comment by Littledesire on February 20, 2009

Very useful blog! I used to sharpen all of my images shot with my previous camera, but not now! Everyone is on the learning curve!




Comments (12)

This article has been read 2116 times. 9 readers have found this article useful.
Photo credits: Christopher Meder.

About me

I'm a freelance and micro-stock professional photographer. I love my work and I see it as an art-form and a discipline of painting with light. To me it's a study of how light and shadow affects everything around us and our own and individual interpretation of the world that we live in.

(Krystof)
Sawtell, AU

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