[Alex-Nelson]

Being a swede I like to read on the swedish website Objektivtest.se which regularly publish really nice lens reviews with MTF-charts and high resolution pictures. They have a huge database to dig from.

Now they have added another Pentax full frame lens to the collection, namely the Pentax D-FA 100mm f/2.8 Macro WR. And they have measured MTF at both full frame and APS-C. The review is in swedish but translates reasonably well with google translate. However, I'm not sure why but google doesn't seem to include the pictures and diagrams in the translated version. So here is the link to the original review in swedish:

TEST: Pentax D-FA 100 mm f/2,8 Macro WR - Objektivtest.se

The reviewer claims the lens to perform better at full frame than APS-C. Apparantly the optical construction is quite old, dating back to the analogue time when there wasn't need for super high resolution glass demanded by todays APS-C-cameras like the Pentax K-3 II.

Any one here who tried it with a Pentax K-1 and can confirm the findings in this review?

Cheers

Alex

[Wild Mark]

Alex, this is what I expect to hear re: performance of legacy lenses. Many will be surprised over the performance of legacy lenses on the K-1.

[Giklab]

Wait, since when is the DFA 100mm a "legacy" lens?

[Alex-Nelson]

Alex, this is what I expect to hear re: performance of legacy lenses. Many will be surprised over the performance of legacy lenses on the K-1.

Have you seen this - Review of six full frame prime lenses for the Pentax K-1 ? Also at Objektivtest.se.

TEST: Sex fasta fullformatsobjektiv för Pentax K-1

[Wild Mark]

Wait, since when is the DFA 100mm a "legacy" lens?

Same optical formula as the F and FA lenses. ......... but yes you can buy now off the shelf new - crazy

[TER-OR]

Don't screw with a good design. I use an FA100 f2.8 and it's a joy to use.

[UncleVanya]

Don't screw with a good design. I use an FA100 f2.8 and it's a joy to use.

I went from the F 100 macro to the DFA 100 WR, and find no real optical difference other than less purple fringing. The weight savings is what sold me.

[pathdoc]

Let's give recognition where due to what is as far as I know the very first D-FA WR lens with Quick Shift, from an era when a full-frame Pentax DSLR was simultaneously a shattered dream and an implausible hope.

[Na Horuk]

Is the DFA 100mm better on K-5 than on the K-3? Because the K-5 has same pixel density as K-1.
And isn't the DFA 100mm one of the sharpest lenses in the Pentax arsenal? If that is not sharp enough, I don't know what is. Throw away any lens you bought for under $700, any lens older than 10 years?
Yes, the DFA 100mm has the optical legacy going all the way back to F, or even previous designs, but it has received updated lens coatings, aperture blades, possibly other tweaks we don't know about, like materials, inner barrel lining.. And Tokina sells their 100mm macro for various brands, and its the same optical formula as this Pentax. Are there complaints about that lens on APSC bodies?

I dunno, I think the DFA 100mm should be plenty sharp on all current DSLRs. Yes, it has a little fringing, and yes, it has a little CA in extreme corners, but it is overall highly corrected, sharp, contrasty, with nice colours. On APSC it should be as good as on FF, but with a slightly higher apparent magnification. I recommend this lens to anyone, as it is a great lens, and very fairly priced. Only complaint I have about it is lack of aperture ring and focus limiter (some older F and FA versions had it)

[pathdoc]

Only complaint I have about it is lack of aperture ring and focus limiter (some older F and FA versions had it)

Not a problem to me, but I understand the desire of some to put a lens of this quality on older film bodies. I don't think any of the manual-focus film bodies offered full, direct aperture-value control of non-aperture-ring lenses, though the Super Program comes closest. I suspect that removal of the external knobs and dials is the price you paid back then for ensuring WR. These days we do have WR lenses with control switches on the outside, so who knows what a reboot of this lens will bring? (I still don't think we'll get the aperture ring back in a hurry, though. )

[Na Horuk]

Not a problem to me, but I understand the desire of some to put a lens of this quality on older film bodies. I don't think any of the manual-focus film bodies offered full, direct aperture-value control of non-aperture-ring lenses, though the Super Program comes closest.

Or extension tubes, bellows, reversals, adapting lens to other systems.. aperture ring can be fairly useful. I understand that some consumer lenses or super-compact pancakes would not have aperture ring, but a dedicated macro prime.. I guess its an unavoidable trend, though.

[UncleVanya]

Or extension tubes, bellows, reversals, adapting lens to other systems.. aperture ring can be fairly useful. I understand that some consumer lenses or super-compact pancakes would not have aperture ring, but a dedicated macro prime.. I guess its an unavoidable trend, though.

It would be reasonably easy to add aperture lever controls like those that exist on the mirror less adapters for these lenses. Essentially you would create a short extension tube with the control. If the market exists it may appear.

[TER-OR]

I just switched from the K5 (base) to K3II, and this year the K3II will be my primary macro lens. Focusing is roughly similar, the K3 motor is faster, though. Resolution is better, that much is obvious already. I'm also playing around with flash a bit, though when it's fully sunny it's not necessary except nice as a filler.

You can see the new albums on my Flickr site, marked 2016. Bear in mind not all the photos at Fermi will be frame-quality. Some of the bumblebee pictures in particular are of bees in flight because that's how you can see the abdomen sometimes, so they're of scientific use if not worth sharing online. Usually in that case I'll have one or two quality pictures and a couple showing other views which help ID.

Out in the field, I let the camera do some things. Generally I shoot in TAv, since settings often don't need to change much. I'm usually too busy trying to get position and track insects to muck around with a manual lens. The ability to quickly switch to manual focus, however, is paramount.

I have considered getting the WR version of the lens, but have spent that money on other gear instead. Still, depending on how much more survey work I wind up doing, I may well get it for safety's sake.

[Alex-Nelson]

Is the DFA 100mm better on K-5 than on the K-3? Because the K-5 has same pixel density as K-1.

Well, yes, and no. The K-3 has a resolution corresponding to a 54 megapixel full frame sensor. And this lens' strength clearly isn't on the resolution side, which you can see if you compare the MTF for full frame, measured at 20 cycles (line pairs)/mm with those for APS-C, measured at 1,5x the frequency - 30 cycles/mm.

Going through the various macro lens reviews at Objektivtest.se I can find several newer lenses that performs better with APS-C. For instance Tamron SP 90mm f/2.8 Di VC USD (TEST: Tamron SP 90 mm f/2,8 Di VC USD Macro) and Canon EF 100mm f/2.8 L IS Macro (TEST: Canon EF 100 mm f/2,8 L IS USM Macro).

So I don't find it that peculiar that the Pentax D-FA 100mm f/2.8 Macro WR reveals its weakness more on a K-3 than on a K-5. It's definitely a sharp lens but not among the sharpest today.

Also check out their review of the Tokina AT-X 100mm f/2.8 Macro. If you look at the MTF it performs more or less on the same level as the Pentax 100/2.8 Macro. Which is logical since they have a similar optical construction. Also the old, classical Tamron SP 90mm/2.8 Macro doesn't quite match the performance of the newer version. The difference is more obvious with APS-C than full frame.

TEST: Tamron SP AF 90 mm f/2,8 Di Macro

Cheers!

Alex