I don't think food shooters like you would even feel the lag at all.

Hi, what else then?

Therefore, knowing what you want to shoot is important.
For instance, it's a tough decision to be made in between 6D and 7D Mk ii, a full frame with lesser AF points against a crop sensor fast shooter with many AF points.

For landscape, nature, and still images, people go for 6D. Whereas, wildlife, people, children and other moving objects, people go for 7D Mk ii.

Am I right?

2. L lenses are expensive- Yes, to me, they are very expensive. There are a few USM lenses that are specially designed for APS-C sensor bodies that are pretty good and highly recommended. Why would anyone still go for L lenses? To me, I can only think of one reason, photographers who use crop sensor bodies have intention to go full frame in the future. So, they will not have to sell all the pricey APS-C lenses and start all over again to buy full frame lenses.

What do they gain?
1. Extra focal length- I have read some reviews that some travel or poor photographers who demand for lighter camera bags or weak monetary ability, they have tendency to use APS-C bodies to shoot wild life photograph. With the same type of telescope lens to be used on APS-C and full frame bodies, APS-c bodies allow the photographers to zoom further. For instance, 70-200mm lens, on APS-C bodies, the photographers are allowed to zoom up to 320mm (200mm x1.6).

Would it not be considered that since FF lens is built for FF sensor, the lens would need to take into account corner to corner sharpness? If you use FF lens on apsc sensor, since the image is cropped, so too does the edge softness being cropped out resulting in very sharp image at the corner. IMO.

Would it not be considered that since FF lens is built for FF sensor, the lens would need to take into account corner to corner sharpness? If you use FF lens on apsc sensor, since the image is cropped, so too does the edge softness being cropped out resulting in very sharp image at the corner. IMO.

not really, 17-40L is a lot cheaper than say EF-S 1755, similarly priced with EF-S 15-85.

Just that 17-40L loses out a lot compared to those 2. 17-55 has f2.8 constant while 15-85 covers more range.
extra focal length if you're looking at telephoto.

they actually lose out focal length when it comes to being wide.

Seriously, if you are on APSC cropped sensor, just get a good APSC lens.

Like 15-85 USM IS. This is very good lens I brought this lens to europe, one lens do all the work.

only down side is floating aperture, f4.0-f5.6, but very nice lens hehe

You probably can get it for RM 1.5k even. 17-40 F4L and 70-200 F4L are under RM 2k, comes with lens hood.

Expensive? Think Canon EF-S 15-85 and EF-S 17-55, and even EF-S 10-22. Non L. Non FF lens. RM 2k+++ and still no lens hood, no pouch either.

Still think L lens expensive?

I know that. This is in respond to why some people use ff lens on apsc sensor.

True, but negligible IMO...

You probably can get it for RM 1.5k even. 17-40 F4L and 70-200 F4L are under RM 2k, comes with lens hood.

Expensive? Think Canon EF-S 15-85 and EF-S 17-55, and even EF-S 10-22. Non L. Non FF lens. RM 2k+++ and still no lens hood, no pouch either.

Still think L lens expensive?