Canon 300mm f4 vs 400mm f5.6

Build quality, handling

If I only see the build quality of the two lens, I would certainly want the 400mm f/5.6. It is well balanced, slim, nice in every aspect, while the 300m is a little front heavy. The stabilizer of the 300mm gives some noise, not loud but it is there. Both lenses built like a tank, can survive I guess even landing on a concrete surface. Both lenses has a built-in lens hood, which can be fixed at the end of the lens.

Optical quality

If we see these lenses has excellent optical quality. Barely any distortion, chromatic aberration, anything. Excellent sharpness, contrast, beautiful colours. The more expensive Canon L primes like the 300 f2.8 or 500 f4 are even better, but with significantly higher price tag. I think most of the people won’t be dissappointed with the pictures these lenses produces. The 300 f4 has a better resolution, even with the teleconverter, but at 400mm the picture quality of the 400mm is better(no surprise). Don’t worry about scientific numbers, both lenses are very sharp as I see with my eyes. Although the 400mm has less resolution on paper, from 20m easiy can identify very thin fur on the pictures wide open at f/5.6.

Brightness

Between the two lens has 1 stops difference. The f/5.6 is for good light, especially paired the 400mm focal length. For sharp shots 1/1000s preferred. The equation end in high ISO in not so good light situations. The 300mm with the f/4 aperture is much better in these cases, if we don’t use the teleconverter, which most people use all the time with the 300mm.

Minimum focusing distance

Perhaps the weekest point of the 400mm f5.6. The minimum focusing distance is 3.5m for the 400mm. Here the 300mm f4 is is much better with it’s 1.5m minimum focusing distance. If your preference is macro with this lens (flowers, bugs, butterflies) the 300mm f4 is better. It is possible to put some rings to help with minimum focusing distance, but this ring has more impact on shorter lenses.

Sharpness wide open

Both lenses are sharp wide open, I think the 400mm is a little sharper at f/5.6, than the 300mm at f/4.

Usage with teleconverters

Both lenses can be used with the 1.4x converters, but the 400mm won’t autofocusing with the Canon converters. With the blue dotted Kenko’s the autofocus is works reasonably. With the 2x converters the quality is not really good, and the viewfinder going to be dark(f8) at the 300f4, very dark, I would say almost useless with the 400mm f/5.6(f11). To check how is it look the picture in the viewfinder, can try the dof button on your camera, with an another lens. The quality with the 1.4 is very good, but don’t expect the same quality as the bare lens. I recommend th newest Kenko Pro converters because of better focusing speed, and barely worse quality. Canon converter’s build quality is better though.

Intended usage

Birds/wildlife, sports, macro, portraits

Birds/wildlife

Don’t expect it is easy to photograph birds with 300mm. The 600-800mm focal length would be the ideal but this is out of the budget for many. 400mm is much better than 300mm. More advanced birders can make pictures with the 300mm also, more easily from the hide. I prefer the lens to be 400mm at least for birding.

Sports, wildlife, portraits

The 400mm is a bird/wildlife lens, the 300mm f/4 is better for all other purposes because of the 1 extra f-stop(brightness) and the wider focal length.

Alternatives:

At this level and price range not many alternatives, for birds/wildlife the new Tamron 150-600 vc to consider. The new Tamron is heavier approximately 2kg, (4 libs), f6.3 at the long end (600mm), but surprisingly good for a zoom. Not so bright or sharp than this lenses. The sharpness at 400mm little below the Canon 400mm. At 600mm I think it is better.

Autofocus

The autofocus of the Canon 400mm f5.6 is a lot faster, than the autofocus of the Canon 300m f/4 is.

Which one to choose:

The one you like. For birds I certainly recommend the 400mm f/5.6 over the 300mm f/4 in bright situations, with a 1.4 extender goes up to 560mm. If you live in a country where the light levels are not so high, perhaps the 300mm is more useful, because of the extra f-stop and the stabilizer. If you like macro for this purpose the 300mm is better, so for portraits, or sports, because of the shorter focal length.

Specifications

Release date

The Canon 400m was released in 1993, while the Canon 300mm f/4 is in 1997.

Optics

If we speak about optics 8 lens elements in 6 groups for the 400mm, and 15 elements in 11 groups (which is many for the prime) for the 300mm is. The 400mm has 1 Super UD and 1 UD element, the 300mm has two UD elements.

The Canon 300mm f/4 is has more resolution even with a converter attached, but the 400mm has better image quality at 400mm especially contrast and colors.

The 400mm is an interesting lens, the resolution is not very high, certain images looks almost grainy if we magnify (little exaggerate), but even with an 1.4x converter the images looks very nice, retaining high contrast, beautiful colors and sharpness. It is hard to find people who is not happy with the 400mm. Of course the longer and brighter more expensive primes are even better than the 400mm.

Both lens has very nice colors and contrast and renders details beautifully.

Focal length

Some people say don’t impressed with the Canon 300mm is at all, but loves the 400mm. The 400mm makes vow images, while the 300mm not. Apart from bad copies, the thing here I think is not picture quality, but more of a focal length issue. With a 300mm it is much harder to get close to a bird or distant animal.

For wildlife especially birds I prefer the 400mm (often with the 1.4x converter), for macro the 300mm is much better because of the much closer MFD.

The weak point of the 400 that apart from birds, it is quite long, and 1 stops slower which means harder to make portraits for example.

Hood

Both lens has a built in hood, which is the best solution according to me. The hood can nicely be fixed at the end position to give a maximum protection for the lens front element. The hood is long, gives a certain length to the lens size.

Minimal focus distance

Minimal focusing distance: 3.5m for the Canon 400mm f/5.6 , 1.5m for the Canon 300mm f/4 is. The 3.5m MFD is hard to get used to if you haven’t used long primes before. The 1.5m MFD of the Canon 300mm f/4 is is not bad.

Weight

The difference is 50 or 60g (2.11 oz.) (1260 vs 1200) which is almost negligible, both lens is easily hand holdable.

Filter size

The filter size is 77mm for both lenses. The 77mm is the most usual among pro lenses. Not really needed any filter according to my perception, except for protection. These lenses give images similar to cheaper lenses with a polarizer, thanks to the exotic Super Ud lens elements.

Compatibility

Full frame, I don’t know anybody who use these lenses for Full frame. 60% of reach immediately will be lost, or other way 60% gain for Aps-C cameras immediately.

The 400m is similar to 640mm on a FF camera. The 600mm lens costs several times more.

Lens mount

The lens mount is of course metal for both lenses.

Manual focus override (FTM)

Both lens can be used with manual focus override, if we don’t like how the lens focusing grab the ring without any switching and change focus position, but the lens will not switch to manual focusing, after pushing the shutter release button starts to focus again.

This is good for example you want the focus to pass a busy foreground.