At below links can be find comparison of different lenses. Usually I compare lenses with the same purpose. For example 85mm lens to a 85mm lens, general usage lens with a general usage lens. Obviously the lenses are not exactly the same in that case nothing to compare. One lens is brighter, the other has different focal lenght. One is a prime lens other is a zoom lenses.
The general rule
The general rule in comparison is “apple to apple” which means for example that we compare the 85mm f1.8 lens to the other lens with the same parameters. This rule is not always applicable, as some time we interested how a ‘Canon L lens’ compare to the ‘non-L’ lens, or we interested a prime or a zoom is a better choice for a specific task.
Canon Lens comparisons
Canon 15-85 vs Canon 24-105 is
Canon 18-55mm is vs Tamron 17-50 f2.8
Canon 40mm vs 50mm
Canon 400mmf5.6 vs 300mm f4 is
Sigma 170-500 vs 50-500
Tamron 150-600 vs Canon 400 5.6
Canon 60mm vs 100mm Macro
Nikon Lens comparisons
What are the parameters to compare ?
For me the most important in a lens parameters is optical quality, what kind of pictures can I make with the lens ? The optical quality consists of several factors see below.
Perhaps the most obvious parameter is that how bright the lens is. How many light can come in? How usable in dark situations ? The really bright lenses has f/1.4 or brighter aperture. Even f/1.8 bright lenses gives big impact on photography compare to f/2.8 usual zoom lenses.
One of the most important factor for prime lenses, very important the range the lens covers in zoom lenses. What kind of focal length we need ? Ultra wide angle, wide angle, normal lens or telephoto ? The most useful in general photography is the wide angle normal lens range. On Aps-C cameras 18-55mm, on Full frame cameras 24-70mm.
The most obvious optical quality is image sharpness, how much detail can be found in the pictures. How clear the image that the lens is make.
The contrast is very important, contrast makes images to ‘pop’, even more visible than image sharpness. The lenses with a really good contrast is possible to make excellent images. If the sharpness or resolution is also excellent gives the lens a very good value.
Colours are also very important, it is interesting how different the colours can be in different lenses.
Build quality is very important, how much time we can use the lens, before replacing ? We have the lens all the time in our hands, how is it feels in usage, is it a joy to use or a frustration ?
Autofocus is realize the lens’s optical qualities. If we have a bad focus, we can through lots of pictures out of the window. A good autofocus helps to catch action and makes pictures otherwise not achievable.
Perhaps the most important factor for many people. If we don’t have a budget, we need to search for other solution.
It is important what we get, for how much amount of money? Is the lens worth to buy it? Do we spent a huge sum for a lens, what we use several times in a year ? It is important to understand what kind of value we can get. This is where many Canon “L” lenses are very good, because these lenses keep their value very strongly even years after we bought them. Why ? Because many of these lenses has excellent built quality, fast accurate and silent auto focus, and many cases fantastic optical quality. But we can’t go blind, as we see an “L” moniker, and think we arrived. Not all Canon lenses are excellent, most of them are very expensive, and one is better the other has not as good value at all. On of my favorite example is the Tamron 150-600mm lens, which cost 1069 USD if you can manage to have it, because must wait months to have a copy. You also can buy a 600mm from Nikon or Canon. How much this set you back? For Canon 600mm f/4 USM II you pay 12,000 USD, for Nikon 600mm f/4 you pay 9800 dollars. Both of theses lenses cost around 9-10 times more than the Tamron. What you get? Better build quality, little better brightness (f/4 vs f/6.3 or f/8 if we speak sharper setting). The cheaper solution is the Canon 400mm f/5.6 + Kenko 1.4 converter, or the Canon 100-400mm I and Canon 100-400mm II versions, or in Nikon land the Nikkor 200-400mm f/4 Mark I and Mark II lenses.
What is the lens good for ? Is this the lens we really need in our photography ? The autofocus performance can greatly enhance or destroy the lens’s usability. Brightness also can help a lot that the lens would be more useful and possible to use in more situations.