@TheRogue wrote:... bring up the 85mm L f1.2 II lens on my laptop screen, I find myself reaching for my credit card! I'm going to be doing lots of portraiture of an intensely breathtaking woman this coming year, and I'm thinking I can't do it without this lens. Do I need help?
Of course. But a) so do most of us, and b) you only live once. There are many good portrait lenses, probably including some lenses you already have. But if you're willing to expend the effort to get the most out of the 85/1.2, you'll almost certainly be glad you did. Depending on who the woman is, and her relationship to you (daughter or granddaughter, for example), you may be very glad you did.
Suppose that instead of photography, you took up golf. Then look at the cost of clubs, club membership, and greens fees, and you may conclude that photography is a bargain. After all, if you get good enough, it's not inconceivable that you could make a little money out of your photography.
There are, I'm almost certain, some in this group who own the lens you're considering. They can advise you on the details. I'm just trying to put you in the right frame of mind, 
@TheRogue wrote:Bob, as always you're completely right about everything! The lady is not related to me but she is breathtaking none the less - so this is my take on it - I owe it to her to use the best equipment! And that is how I'll sell it to the wife who is ever understnding of my pursuits in the visual arts.
I did consider golf, in the dim and distant past!
By the time I post, I have usually made up my mind about a purchase - I kind of use the forums to find any reasons NOT to purchase. My recent purchasing conundrum regarding the M5 and EOS lenses being one such case where I was swayed away.
Many thanks for your 'esteemed' input!
By the time I post, I hope your mind is made up. Because I'm throwing some gasoline on the fire. I love this photo. It's a customer shot from B&H, from the lens' product page.
I love the focus gradient that is present in the background. The focus fades from razor sharp to a beautiful creamy blur.
I'm so happy that your mind is already made up to buy the lens.
I think I currently have 9 lenses and while I have "rented" the 85mm f/1.2, I don't happen to own that lens. I don't tend to do a lot of portrait shooting so it was difficult to justify owning my own copy. The two alternative lenses that I like are the EF 135mm f/2 as well as the 70-200mm f/2.8L (I now own both the version I and II of that lens) and I use it near the 200mm end.
But while I love the look of the long focal length + low focal ratio lenses, it does, of course, mean putting the camera much farther from the subject. Which is why... if I were doing a lot of portraits, I'm sure I'd be lined up to buy my own copy of that lens. It's a fabulous lens.
Having rented it, the two things I noticed are (a) it's slow to focus (much slower than most other USM lenses) so it's not ideal for situations where you plan to focus & shoot on the fly (use the f/1.8 version if that's the sort of use it'll get). For non-candid photography where you're setting up the shot... this isn't an issue. And (b) it does have axial (longitudinal) chromatic aberration. I focus test all my lenses using a test chart. When doing this with my rented 85mm f/1.2 I did notice that as I adjusted focus, there's an overall color shift with red fringing vs. blue fringing around the high-contrast focus chart pattern.
Here's a sample (I've cropped in on this to make it easier for you to see) that I shot with my rented copy.
Notice that the lines on the scale above the 0 mark have a slight blue fringe to them and the lines beflow the 0 mark have a slight red fringe. These are proper millimeters so you can also notice that after about 1.5 centimeters of the focus point (assuming using a shallow DoF -- these were shot at f/1.2) that the blur hides the CA and you can't really notice it. You're unlikely to be shooting true black & white high contrast subjects so this is something that probably wont show up (hence... you can find lots of gorgeous images shot using this lens). While the effect is there, it's not the sort of issue that would put me off from buying the lens (because I don't think it would show up in a typical "portrait" image of a real subject.)
@TheRogue wrote:
People, I think the decision is made - this lens is destined to be in my bag!
I see this in your future... 🙂
