Tamron 85 f/1.8 Di VC USD

[stenrasmussen]

Thank you Sten. Good to know.

If you still have both lenses, you might be interested if the Tamron is also rather a "real" f2 than a f1.8, like the Nikkor. (Nikon Marketing seemed to be very progressive wrt to this value)

Just compare the exposure level at open aperture and a fixed exposure time. Take a good f1.4 lens, set it to f1.8 and use it for comparison as well.

enjoy your new lens,
Andy

I haven't measured this but can say that the Nikkor i "darker".

[Andy]

Thanks, Sten.
Then you have one more reason for your decision 

enjoy and rgds,
Andy

[Thomas G]

Sten,
thanks for all the effort and posting.
Have been reading with interest from the beginning and will continiue to do so.
I consider an 85mm/1.8 being part of my wishlist but unsure which.
The Tamron seems to open up the game ...

[Roland Vink]

Also note how the Tamron's focal length is slightly longer.

I expect both are close to 85mm at infinity and far distances, however both are IF or RF designs so the focal length reduces at close range. The Nikkor apparently has more focal length shortening than the Tamron. This is confirmed by the magnification at the near limit - both focus to 0.8m, and while the Nikkor gets to 1:8 ratio, the Tamron can crop more tightly to 1:7.2 ratio, due to the longer focal length. Another point in favour of the Tamron. (Personally I would prefer it to focus even closer and achieve magnifications like the 35 and 45mm models, but I guess that would take sales from their 90mm macro)

[Roland Vink]

Bokeh: Tamron still in the lead as shown in the f/1.8 and f/5.6 examples below.

It's hard to believe both shots were taken at f/5.6, the amount of blurring on the background tree looks so different - looks at least a stop apart, even after considering the slightly different focal length.

Point light source stars - the Tamron produces pointy ones, the Nikkor fan shaped ones. I like the former.

That means the Tamron aperture must be circular only at wider apertures, when stopped down the blades only show straight edges around the opening, which gives more sharply defined diffraction stars. The Nikkor aperture opening must remain more rounded, even though it has fewer aperture blades (7 vs 9)

[Akira]

Sten, thanks for sharing further results.

As Roland pointed out, the difference of the focal length are surprisingly large, even being aware that many modern lenses shortenes their focal lengths when focused closer.  So far as the pure optical performance is concerned, I would have to say that Tamron is the perfect winner.

[Hugh_3170]

Sten, thank you for your postings on both the Tamron 85mm and your Sigma 50-150mm.  Much appreciated by many of us, even if some of us (such as me) have not bothered to always thank you for the testing and the write-ups.

It is heartening that both these manufacurers, and Tokina, are producing lenses that take it right up to the offerings from the "big two".  All of these three offer AF.  If MF is also considered, then Zeiss, CV, and others help sharpen the competition.  Good for the consumer, even if somewhat challenging to match the offerings to ones needs.  (And I won't even get into matching against ones "wants"  )

[stenrasmussen]

Here are both lenses stopped down to f/5. If anything the Tamron blades seem to form a rounder rounder opening due to its 9-blades but the intersection between the blades looks a little sharper.

[stenrasmussen]

Both lenses at infinity and at ca. 82cm focus distance:

[Roland Vink]

Both lenses at infinity and at ca. 82cm focus distance:

At infinity both images line up perfectly on the left, the image take with the Nikkor shows just a little more on the right, so the focal length must be very slightly shorter, but there is hardly anything in it.

At close range the Nikkor sees 332mm side to side, which is about 1:9.2. The Tamron sees 300mm, which is about 1:8.3. If you continued to the close focus limit I can see how this would translate to 1:8 for the Nikkor and 1:7.2 for the Tamron, as specified by the manufacturers.

[Roland Vink]

Here are both lenses stopped down to f/5. If anything the Tamron blades seem to form a rounder rounder opening due to its 9-blades but the intersection between the blades looks a little sharper.

I agree. Both openings also look very similar in size relative to fully open setting. That makes it even more surprising the two previous shots at f/5.6 show such different size blur circles in the background.

It may be changes in angle or lighting, but the coatings of the Tamron also look more transparent. Does that also translate to better contrast and resistance to flare? The Nikkor also has a bit of dust

[Roland Vink]

<delete - double post>

[Akira]

Sten, yet another intriguing result!

According to JIS, Japan Industrial Standard, 5% of discrepancy in the indication of the focal length in the spec sheet is tolerated.  So, the difference between the two lenses focused at infinity should be nothing to be particular about.  But the difference in the closest range is rather surprising to me.

Also, I feel that the difference of the bokeh or the striped vase is larger than I would expected even considering the difference of the effective focal lengths of both lenses, which was also apparent in the images of the window posted in this thread previously.

[stenrasmussen]

Here's more proof to as why I like the Tammy better: King Bob with his bigger than human adult head shot at a distance of 1.9m (good head portrait shooting distance with FX). Look at 'em blurry ones to the left...

[stenrasmussen]

Outdoorsy, Df and Tammy at f/2.2. This is one sharp lens!