Canon 100-400mm L IS lens question

[jbg232]

I have been looking at this lens for a long time and will likely take the plunge in a few weeks. I know that there are good and ok copies of this lens. My question to people who own this lens is what is the f-stop that it should be sharp above at 400mm for it to be considered a good copy? I will be using it for birding so it will be at 400mm 90% of the time and thus need this tele to be very sharp at that focal length.

 

[Phrasikleia]

This page will give you your answer. Just click on the Blur Index chart. At 400mm, that lens will be sharpest between f/8 and f/11.

 

[FX120]

A good copy will meet the published MTF charts:

http://www.usa.canon.com/consumer/controller?act=ModelInfoAct&fcategoryid=150&modelid=7344

Center of frame it should be sharp wide open, and very sharp at f/8

 

[AlaskaMoose]

I have been looking at this lens for a long time and will likely take the plunge in a few weeks. I know that there are good and ok copies of this lens. My question to people who own this lens is what is the f-stop that it should be sharp above at 400mm for it to be considered a good copy? I will be using it for birding so it will be at 400mm 90% of the time and thus need this tele to be very sharp at that focal length.

Once you have looked at the links provided by others (above), go to this one, and see what others have to say about it. Just click on the lens, and then see the photo samples and comments.
http://photography-on-the.net/forum/showthread.php?t=141406

For birding at 400mm, a cheaper lens, EF 400mm f/5.6L prime is hard to beat for sharpness, but with lots of daylight. Click on this lens, too, and see the images there.

 

[PCMacUser]

As AlaskaMoose mentions above, the 400mm f/5.6 is worth looking at if bird photography is your 'thing'. It's considered to be noticeably better than the 100-400mm. I don't own either but this is what I've learned from those that do.

 

[Kronie]

Mine is best at around f/8 @400mm. If 90% use will be at the long end AND "very sharp" is imperative, I would suggest the 400mm prime. The 100-400 is a compromise lens and while its quite usable at 400mm a prime lens would smoke it.
Here is another link that may help. You can clearly see the resolutions quite bad at 400, best at 100 to 200.

http://www.photozone.de/canon-eos/204-canon-ef-100-400mm-f45-56-usm-l-is-test-report--review

Still worth getting if you need the range.

 

[vga4life]

Mine is best at around f/8 @400mm. If 90% use will be at the long end AND "very sharp" is imperative, I would suggest the 400mm prime. The 100-400 is a compromise lens and while its quite usable at 400mm a prime lens would smoke it.
Here is another link that may help. You can clearly see the resolutions quite bad at 400, best at 100 to 200.

http://www.photozone.de/canon-eos/204-canon-ef-100-400mm-f45-56-usm-l-is-test-report--review

Still worth getting if you need the range.

The 400 f/5.6 doesn't have IS, which may or may not be a consideration. I like the combination of the 300mm f/4L IS and a 1.4x teleconverter. Quality is still better than the 100-400mm at the long end.

 

[jbg232]

I had strongly considered the 400mm prime but did not go with it for two main reasons. One and most importantly, the IS allows me to take pictures under more lighting conditions (which is a consideration in heavily forrested areas) and two, I wanted to have the ability to zoom out for occasional shots (90% not 100% zoom usage). Also, from my reading (although the link above denies this I have seen others berate that link) the 400mm zoom is as good as the prime IF you get a good copy. Hence, the reason for my post here as to what defined a good copy...

 

[AlaskaMoose]

The 400 f/5.6 doesn't have IS, which may or may not be a consideration. I like the combination of the 300mm f/4L IS and a 1.4x teleconverter. Quality is still better than the 100-400mm at the long end.

That exact point (300mm f/4L plus tele) has been brought up at the Canon forum (link I posted above). According to some photographers, once you add a 1.4x teleconverter to the f/4 lens, you would be better off with the accurate and fast-focusing 400mm f/5.6 lens on a tripod. Not only that, but IS is designed to reduce hand shake, and IS does not work well when mounted on a tripod. Are you going to handhold the 300mm f/4L? In that case, IS is great, but this feature makes a lens bulkier and heavier than an equal lens without it.

The 300mm f/4L IS weights 2.6 pounds, while the 400mm f/5.6L (no IS) weights 2.8 pounds. The 300mm one has 11/15 groups/elements, while the 400mm one has 6/7 groups/elements. The 400mm one is 10.1" long, while the 300 is 2" shorter.

 

[PeteB]

I think I'm a rarity of enjoying my lens wide open.

100% crop

But you need good light and a good eye for focus through the viewfinder.

You also need to be aware of how fine the DOF can be, which can easily mislead the unaware to beleive that the lens is soft wide open. I guess that some might be, but some slight movement, or mis-focusing can cause softness. Compare the softness of the eye against the sharpness on the bird's shoulder.

 

[osin]

You said that you are going to be at 400mm most of the time so the only smart move here is to get 400mm f/5.6 prime. Much sharper,faster, lighter and cheaper than a zoom. You can buy it used for about $925 on many forums...

 

[jbg232]

Except for that 10% of the time that I want to zoom out. Plus the fact that the 100-400mm IS lens has IS which allows a lower f stop at the same amount of light and the fact that good copies of the lens will produce the same results as the 400mm prime, hence the reason for the post (ie what defines a good copy of this lens)?

 

[AlaskaMoose]

Except for that 10% of the time that I want to zoom out. Plus the fact that the 100-400mm IS lens has IS which allows a lower f stop at the same amount of light and the fact that good copies of the lens will produce the same results as the 400mm prime, hence the reason for the post (ie what defines a good copy of this lens)?

Lower f stop? Perhaps:
http://photography-on-the.net/forum/showthread.php?t=652578

 

[Grimace]

and the fact that good copies of the lens will produce the same results as the 400mm prime, hence the reason for the post (ie what defines a good copy of this lens)?

Simply, no. It is definitely softer from 340-400mm, unless you get down to f/8. On the other hand, the 400mm prime will be sharp wide open.

Get whatever you want, but if you are looking for sharpness at the far end, the 400mm prime is what you want.

 

[mikekelley]

To OP:

Ask this question HERE and you will get the answer you are seeking. I've seen that discussed many times on those boards.