I don’t know about you, but I always do a little research before dropping hundreds or thousands on a new lens. Not all review sites are the same, but between these select few you should be able to get a good idea of what to expect from any given lens you may be thinking of purchasing.
With the holiday season upon us, I thought I’d share a few links where you can find a good variety of lens reviews.
Don’t forget the used lens market either. I’ll cover that subject in a future post. For the time being, here are the web sites where I normally do my lens research.
Optical Limits: Good selection of reviewed lenses with actual test data.
DXOMARK: More focused (no pun intended) on optical quality but very good reference for comparing lenses on different camera bodies.
Imaging Resource: One of my favorite general photography web sites. They do a very nice job of testing and reviewing lenses and other gear. Nice articles too.
LensTip: With over 1,500 lenses reviewed, it’s definitely a place to visit. They have tested many lenses that other review sites seem to have missed.
Are lens profile corrections always necessary? Take a look at the two photos above. You tell me which one looks better.
If you are like me, when I edit a photo I automatically add a lens profile correction to the image when it is imported.
When it comes to post-processing your photos, I don’t think it’s always necessary to correct for the lens and as a matter of fact, sometimes you can improve the image quality by not correcting for lens distortions and vignetting.
What you talking about Gary?
First, I think it’s always a good idea to remove visible chromatic aberrations from the image. You know, those red, blue or green lines on the edges of objects in the photo. Some lenses are better than others when it comes to this; however, all lenses are not the same and some of my lenses introduce no noticeable CA. If CA is not visible, there is really no reason to remove it. When you click that remove CA button, the editing software will shuffle pixels to make it look cleaner. Every time you shuffle pixels in your image, you reduce the effective resolution of the lens. No way around it.
Lens distortions can be obvious in some images. Buildings or objects geometry can be obvious but it can also not be noticeable. You may want those trees to align vertically on the edges of the frame, fair enough. Go ahead and correct it. But, sometimes your image will have no obvious distortion due to the subject matter and content of the composition. Every time you click the correct lens geometry the image is re-sampled and those pixels get shuffled. Every time you reshuffle the pixels in your photograph, you lose resolution. If there is no obvious geometric distortion in your photograph, why shuffle the pixels to correct it? You’ll be hard pressed to see a difference. If you examine your shot up close, that small loss of image clarity can be noticeable though. If you can’t obviously discern a problem with distortion, why correct for it?
How about vignetting/shading? Some lenses will produce a visual drop-off in brightness as you move towards the corners of the frame. There are several things at work here, but vignetting is the most obviously visible artifact. If it bothers you, remove the vignetting. Keep in mind though, further editing to reintroduce that vignetting is going to shuffle pixels. When you shuffle pixels in the image, you lose resolution. No way around it. Plus, adding vignetting back to an image that has been corrected is making two corrections for something just to get back to where you started. Why correct it to begin with? You can manually shade the corners if you like but you don’t need to reshuffle pixels to do it.
I add vignetting to a lot of my images. It draws the eye into the frame. It’s an age-old photographic technique. You really need to decide for yourself if you need it or not, but if you do want it, don’t correct for it. Let the lens do the talking and reduce the number of steps in your workflow.
Read any lens review and they will tell you how easy it is to correct for CA and distortion in post processing.
It’s even easier to not make the corrections, and the visual results can be exactly what you where hoping for to begin with.
I’ve been playing with a vintage Nikon lens on the D810.
The Nikkor 35-70mm f/2.8 D
An older lens built in the day for use on their film bodies, this lens can be found dirt cheap on eBay for between $200-300. 20 years ago, this was a professional grade lens and it was commonly used by photojournalists. Production ran from December 1987 through 1992.
Today, it’s been relegated to the odd collectors item.