secwind - see the 1:1, 4:3 etc. marks on the sheets you've printed? You want to line the camera up so you're taking a shot that covers the 3:2 marks (i.e. you end up with the four crosses in the corners of your shot).
That will mean you'll be pretty close, and will be pushing the limits of your printer, so it's better to try to print the chart over several sheets and stick them to a flat backing board (oh, and flat is also a tip - I see the sheet on the left is curved up off the floor).
OK, so that was the helpful bit, now I'm gonna hijack your thread as I'm in exactly the same position and was going to post a thread on the subject today, but it seems more sensible to keep it to one .
I've just bought the 14mm too, and I'm unsure if my expectations are realistic. At the moment I'm testing it against an EF-S 15-85 on a 7D (which I appreciate means I'm not testing the whole of the Samyang, but if anything, that should give it an advantage).
I'm pretty certain my 15-85 is a good one, as I've previously tested it against two different copies of the Canon 14mm f/2.8 L II, and whilst the L was sharper at the edges, the zoom certainly wasn't shamed.
I've tested my Samyang on both distant (landscape) shots and a test chart and results are pretty consistent:
- At f5.6 and smaller the Samyang is pretty good vs the 15-85
- It's noticeably better than the zoom on the left quarter of the frame
- However, in the center and right it's not quite as sharp as the 15-85 (apart from the extreme corners)
- At f4 and wider the Samyang is pretty bad - very 'dreamy'; though it just about recovers on the left side of the frame vs the 15-85
- Big. Big vignetting, even on a crop, even at f5.6
- All testing on a tripod, mirror lockup, timer, liveview focusing at 10x
Based on the reviews I've seen (where - the majority of - people have got a good one) I'd expect the Samyang to at least match the 15-85 at all equivalent apertures, and likely be a fair bit better. The fact it's not really usable until f5.6, and even then struggles in the center/right of the frame vs an EF-S zoom makes me suspect I might have been unlucky.
Hoping someone reading this has seen both good and bad copies and could comment on whether I'm being unrealistic, or if this does appear to be a bad one?