Laowa 100mm 2.8 on Fuji x mount ?

eladrill2 wrote:

Thank you all for your suggestions. Now, a couple of additional questions.

In terms only of sharpness,

(1) Is the canon ef 180 3.5 mounted on fuji the sharpest of the listed primes?

I can't offer any advice on that question.

(2) comparing categories, overall, are the fuji zoom lenses (xf 50-200 and 70-300) sharper than the above primes (mounted on a fuji camera via adapter)?

I owned the 55-200 for some years but sold it for the 70-300 to get the extra reach.  The 55-200 from about 55-150 is really very sharp - excellent.    The 70-300 is better than the 55-200 at the longer FLs and offers great close-focusing at all FLs.  It's also sealed, and TC compatible.

I would rate both zooms as little different in sharpness from primes in the central area.  In the outer image, good FF telephoto primes used on APSC tend to give very good IQ because they were designed to cover FF - so well beyond the APSC corners.  That's a general observation, but I can tell you that it applies to a comparison between my FF Canon FD 300mm f4 prime and the XF70-300.  It's only an incremental difference, but it's there.

Having acknowledged that, I don't think it would make much difference at all in applied photography - for two reasons. The first is that telephoto subjects tend to be in the central part of the image - people are less concerned with corners when using telephotos than when using WA lenses for subjects like landscapes.  The second is that the difference would be irrelevant in anything other than very large prints - larger than I actually make.   I compared them and kept the zoom despite the difference.

I would look to reasons other than sharpness when considering modern zooms.  Whatever slight differences might be detectable under very controlled conditions, you have to hand it to the native zooms compared to adapted lenses for integration (depending on the prime lens in question and adapter).  That's for some or all of....

• FL flexibility
• OIS
• AF
• close-focusing
• focus bracketing/stacking
• LMO, and
• EXIF

Personally I find FL flexibility and OIS to be the great benefits of using a telephoto zoom.  Primes may offer higher speed, but with telephotos you often can't change position or change it far enough to alter composition significantly.  So then a prime may not meet your needs.  And good zooms are so sharp that they easily out-resolve a crop from a shorter prime.

Primes win for aperture if you want subject/background separation.  They can also offer a smaller and lighter option than a 600g zoom.  That's if you keep to adapting a short FL - say a 100-135mm and you deliberately pick a small, light option from the many legacy lenses available.   If you start adapting longer lenses -  180mm, 200mm and 300mm lenses -  primes (+adapter) are no lighter than the 70-300 and may well be heavier.

Hope that helps.

Cheers, Rod