When it comes down to it, some Nikon glass is better than the equivalent piece in the Canon lineup, and vice versa. The advantage of Canon over Nikon is in the auto-focus, moreso with the big long lenses because in the EOS system, the focusing motor is built into the lens, not in the body, so you get the right size motor for the lens. Nikon has more recently compensated for this with their big lenses by adding booster motors to speed autofocusing. This also leads to reduced battery life by having two motors to run, but this is a problem unlikely to be observed by most of us - if it rears its head at all, it only happens for the pro action photographers who are firing off hundreds if not thousands of shots in the course of a single sporting event, all of which are shot with 400 f2.8 or 500 f4 lenses.
It's not flashy Leica glass, but you can't beat the original SMC Pentax (no -A or -M) series for a combination of price and quality. Pentax produced several lenses that, while slow, surpass faster lenses even wide open You can either "spend" lens groups for speed, or you can spend them on correcting various abberations. I can confirm that my SMC Pentax 35mm f/3.5 is a gem (as is my medium format SMC Pentax 6x7 75mm f/4.5, and my SMC Takumar 35mm f/3.5 that preceded it, I'm virtually certain both are direct copies). I just picked up a SMC Pentax 28mm f/3.5 on the same impression. I haven't shot it yet as it needs some cleaning, the aperture is a bit slow.
Pentax's Super Multi Coating is a major boon. It virtually eliminates flare and was DECADES ahead of its time. After the patent expired virtually everyone (that is, everyone who hadn't licensed it already) quietly copied it. They also were way ahead of the game with regard to normal lenses - the Takumar 50mm f/1.4 was definitely in the upper tier in its time and still holds its own today. I don't think there was even another 50/1.4 SLR lens at the time. Maybe Nikon had a pre-AI lens out, but it'd be close.
The Pentax ME is an incredibly underrated camera. It's a 1.0x (actually, 0.97x or something) magnification SLR with a standard split-prism focusing screen. Compared to any other SLR I've handled, including my K1000SE, it feels like the same difference as between an IMAX screen and a movie screen. It's bigger, it's brighter, it's better, period. You can buy the original ME for $20-30, it's absolutely the best deal in film photography. Throw a $50 50/1.7 on the front and you'll have an incredible setup. Forcing yourself to use a normal lens is incredibly for your composition skills, just take that one lens out on a walk and you'll feel better about yourself.
The one thing to note is that in my opinion, M42 glass is superior to K mount glass because the K-mount aperture lever is forced wide-open by the plastic square frame inside my Canon 40D. If I rotate the lens to the 'lock' position, the lens is stuck wide open no matter the aperture setting. I think this may be a peculiarity of the adapter, but you have been warned. Also, you should spend at least the $20 a manual focus screen off the auction site will cost you. It will make manual focus ***incredibly*** easier. You could even pay for a Katzeye or a real glass screen, it will probably be even better.
Zeiss, Rollei, or Leica glass obviously needs no introduction. I also absolutely adore my Nikkor 105mm f/2.5, it's extremely sharp wide open. This is what's left after I crop away 75% of the image, wide open. I simply don't give it a second thought, it's an absolutely amazing lens despite minor pitting on the rear element.
Yashica Yashinon DX 50/1.7, an absolute gem of a lens. The Yashinon Tomioka 55/1.2 is nice, but not cheap. Some of the old Sears, Ricoh, Chinon, and Revue M42 lenses are also quite good. Mamiya Sekor made some excellent M42 primes as well.
^^^ Yashinon is also underrated in my opinion. It's not a digital-mountable lens, but I love my Lynx 14E, it's fast and sharp at f/2 and usable at f/1.4 with a heavy body and mechanical leaf shutter. It's the best party and low-light camera for under $1500. (it costs $90).
Also, Fujinon M42 glass. Fuji did and does a terrible job of marketing their products. Look at their large format lenses, they marketed a single and a multi coated product under the same name and the only difference is that one is marked on the inside and one is marked on the outside of the lens (despite different coverage). They left poor Kerry Thalmann to puzzle out what they did. Their terrible job announcing the reorganization of their film line makes more sense in that respect. They have always sucked at marketing their products.
That said, the products are GREAT. Fujinon LF lenses are completely in line with Zeiss, Schneider, Nikkor, and any other manufacturer you care to name. I'd bet their 35mm lenses are too, and they're CHEAP. You may have to clip some aperture pins to make infinity focus, but it'll be a $40 lens so who cares?
From 50+ of M42 lenses I had, I would recommend the following:
East German M42:
Flektogon 20mm/f4 - Top landscape lens that is quite sharp stopped down. Many claims it has no distortion but that's not entirely true. My fav landscape lens after Distagon 28mm/f2.8.
Flektogon 35mm/f2.5 MC - Very sharp in the middle even wide open but not so at the edges unless stopped down. Close focusing (20cm?) is very handy. I would rate this is one of the best East German lenses. Single coated 35mm/f2.8 version flares alot and interfere with EOS mirror.
Pancolar 50mm/F1.8 MC - I like the colours it randers. Quite sharp wide open. Single coated 'zebra' is as good. Unfortunately the Pancolars will interfere with EOS mirror.
Sonnar 135mm/F3.5 MC - Produces smoothest bokeh. Bitingly sharp. It gets a fair share of votes for the best manual focus 135mm lens.
Jupiter 9 85mm/f2 - You love it or you hate it. The swirling and fuzzy bokeh can be distracting. Only useful stopping down to f5.6 and beyond.
Tair 11A 135mm/f2.8 - I think this is the sharpest Russian lens ever made. Good bokeh as well.
Jupiter 21M 200mm/F4 - Quite sharp wide open. Buttery bokeh. Very bulky though.
Pantax Takumars are generally very good. However, the 'favorite' 50mm/f1.4 will interfere with EOS mirror.
ZEISS glass for the win!!!
What about the helios 58mm f2?
That Tair 135 2.8 is exactly what I have been looking for. lots of aperture blades for clean background rendering and super-low aperture. Come payday I think I'll snatch one up.
There is a tutorial floating around on Flickr for converting the Yashinon DX RF lens for mounting on Micro 4/3 digital cameras.
Originally Posted by PaulMD
This is for "G" series lenses, so I don't know if it would be apropos "as-is" for the Lynx or Minister lenses.