Hi everybody,

I would like to open up a thread dedicated to one topic:

DA lens on Full Frame: a sticky test shots thread.

This thread shall be dedicated to test shots of a DA lens mounted to a full frame body (e.g., a film camera body). By test shot, I mean shots dedicated to evaluate the performance. Shots of ordinary subjects aren't suitable to this task, normally, and should not be posted. So, these are the rules:

• K mount lens dedicated to the APS-C form factor is used.
• Image is taken full frame 36mm x 24mm.
• Lens hood was removed.
• And ideally, no filter is mounted.
• The aperture used is specified (note that film cameras don't record EXIF...).
• Sample image shows the entire field of view.
• Sample image(s) show(s) corner, border and center performance at 10MP-100% (multiple crops, or single not-resized image).
• The subject is such that resolution and vignetting at the borders can be compared to the center.

The idea behind this thread is obvious: To compile enough data to assess the spectrum of available lenses for a forthcoming full frame DSLR in K mount.

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Table of results as obtained in this thread (updated regularly):

SMC Pentax-DA primes...

• DA 14mm F2.8: - (clawhammer)
• DA 15mm F4.0: - (Zav)
• DA 21mm F3.2 Limited: - (Boris Liberman)
• DA 35mm F2.4 AL: +++ (aurele ;like FA35/2.0 and no vignetting) (frank)
• DA 35mm F2.8 Limited Macro: 0 (ryno), + (@ 1.15 crop)
• DA 40mm F2.8 Limited: +
• DA* 55mm F1.4 SDM: +++ (aurele)
• DA 70mm F2.4 Limited: +
• D FA Macro 100mm F2.8 WR: +++ (officially specified FF by Pentax)
• DA* 200mm F2.8 ED [IF] SDM: +++? (common belief, but is it true?)
• DA* 300mm F4 ED [IF] SDM: ++ (officially rated "designed for FF" by Pentax patent US7715116)

SMC Pentax-DA zooms...

• DA 10-17mm F3.5-4.5 Fish-Eye ED [IF]: FE, see #59, #61, #94. 10mm: heavy vignette / 14mm: almost no vignette / 17mm ++ (Reps, froeschle, Gooshin)
• DA 12-24mm F4 ED AL [IF]: - (below 16mm, xitek.com), o (at 18mm, architorture), + (at 20mm, architorture), ++ (at 24mm, architorture)
• DA 16-45mm F4: - (below 21mm, Nesster)
• DA* 16-50mm F2.8 ED AL [IF] SDM: - (xitek.com)
• DA 17-70mm F4 AL [IF] SDM: - (KjetilH)
• DA 18-55mm F3.5-5.6 AL: - (at 18mm, Spongefingers; below 23mm, xitek.com)
• DA 18-55mm F3.5-5.6 AL II: missing
• DA 18-250mm F3.5-6.3 ED AL [IF]: - (xitek.com)
• DA 50-200mm ED: -
• DA* 50-135mm F2.8 ED [IF] SDM: - (elho_cid)
• DA* 60-250mm F4 ED [IF] SDM: ++ (officially rated "designed for FF" by Pentax patent US7489452) probably good on full frame but evaluation still missing; the rating is +++ with a baffle modification, + without)
• DA 55-300mm F4-5.8 ED: 0 (+, ++ at tele end, viking79)

Sigma K mount DC...

• Sigma 18-200mm f/3.5-6.3 DC: -
• Sigma 10-20mm f/4-5.6 DC: - (below 14mm, Gooshin)
• ...

Tamron K mount Di-II...

• ...

Overall rating scale:
+++: no significant difference between APS-C and FF corners
++: difference but usable at full aperture with a small loss in corner IQ only
+: usable staring at f/4~f/5.6, with no or a small loss in corner IQ only
o: usable at f/11 or with big loss in corner IQ only
-: not usable

[huanjia]

Steelski, I do not want to discuss another forum too much. So, let me make the following, short comments:

- You're right, post #177 said f/1.4. I don't remember why I thought it is f/8. But too tiny to evaluate resolution anyway.

- There is a new post #234 - #237 with a resolution test at f/1.4. Unfortunately, those guys don't realize that the ISO 12233 test chart is limited to 2000 LW/PH and even show crops of the chart where it is limited to 1000 LW/PH! So, all we learn is that 1000 LW/PH are resolved. Why I produced my own version of the ISO 12233 test chart to measure up to 3000 LW/PH (limited by my scanner & printer, not the chart). Note that 3000 LW/PH is the K20D sensor's resolution.

- Vignetting from the hood is normally pretty obvious. And not visible from the f/1.4 shots. So, those shots either are w/o hood or the hood doesn't cause vignetting. The angle of the 55mm is almost 43° in the corners. If the hood isn't vignetting then this would mean that it was designed to work on FF too. But we still lack resolution figures. Untill we can give it a +++ rating we don't really know.

I went over these posts on Xitek.com, the post #177 said f8 but it's about something else, not related to the MZ_S DA55* photo in post #178. author of poster 178 did not give information on aperture used, the f1:1.4 under the photo is only a description for lens used.

Post #234 - #237 are taken by digital body, not related to our topic, they are comparing 1650 50135 and 55.

actually #177 is the only post with photo regarding DA55* on film body

[danielchtong]

DA lenses are not full-frame lenses, barring the 40mm,

Well I know another confirmed exception.
DA*200mm is actually a repackaged FA*200mm except that the former is weather-sealed and SDM equipped.
Both share exactly the the same optics.
I had it confirmed before buying that

Daniel

[danielchtong]

[DA?200F2.8???] PENTAX DA?200F2.8 ?????? - Pentax Fans Club


Unfortunately it is in Chinese. But the images of this lengthy comparison has confirmed way back that DA* & FA*200mm have the same optics

[architorture]

So, as I promised I got my hands on some free time and a good scanner and finished things off for my test of the DA 12-24 on film.

I scanned the negatives with an Imacon 949 at 4000dpi. For the sake of posting I then resized down to 3200dpi and made 500x500 crops from the center and extreme corner of each frame. This is about like looking at a 13MP image at 100%. I have applied absolutely zero sharpening in the process (flickr made the jpegs though).

Since 2crops x 2 apertures x 5 focal lengths = 20 images I am providing the link to my set on flickr rather than post so many images in the forum. You can see them all (including the full-frame noritsu scans of each) here.

CONCLUSIONS
If you'd rather not take the time to look, here are my conclusions:

- mechanical vignetting disappears ca. 18mm regardless of aperture

- corners actually look sharper @ 12 than the intermediate focal lengths, but of course to use them you would have to crop the film considerably (to aps-c size)

- @ f/4 corner blurring does not reach "acceptable" levels until 24mm

- @ f/8 corner blurring is "acceptable" at 18mm, pretty much a non-factor at 20mm and 24mm

- I do not see much difference in the center btwn f/4 and f/8 in resolution, but f/8 maybe has more contrast (light could have changed though).

- lastly, I think the mechanically vignetted pictures are kinda cool looking, though you will get people asking if it is a fisheye lens because it looks like a circular fisheye to the un-knowledgeable.

I hope I have not forgotten anything, and that this is helpful to others. I wish I had more DA lenses to try!

[froeschle]

According to this blog the DA 60-250 shows vignetting from about 85 to 250mm (see pictures; google translate indicates: "food [=hood?] was removed", "all open F4"). The lens thus seems not to cover FF.

[elkarrde]

According to this blog the DA 60-250 shows vignetting from about 85 to 250mm (see pictures; google translate indicates: "food [=hood?] was removed", "all open F4"). The lens thus seems not to cover FF.

i had no film in my P5 when i had the opportunity to test the DA*60-250, so no photos were taken, but there were absolutely no signs of even slightest vignetting through the whole range in a viewfinder. if it vignettes, it's only slightly.

[froeschle]

through the whole range in a viewfinder

Even if you were looking through a viewfinder with 100% view of field it could be difficult to see "problems". However, vignetting is obvious in the pictures and - contrary to intuition - increases with increasing focal length.

In addition, there is the question, whether a lens is also properly corrected in the extreme corners. This is e.g. not the case for the DA70 (according to Arnold in the dfn ).

[falconeye]

the DA 60-250 shows vignetting from about 85 to 250mm

but there were absolutely no signs of even slightest vignetting through the whole range in a viewfinder

+1
I did the same film camera VF test. No visible vignetting.

My resolution test of the 60-250 is still pending.

Meanwhile, I have strong problems with the credibility of the vignetting report above. The vignetting at 250mm should be very strong. But invisible in the VF?

And I made another test too:

you can looking thru the lens (from behind) and you'll see the aperture's exit pupil. Fully open, it is circular. If you turn it slightly left or right, you'll see that the exit pupil becomes obstructed (not perfectly cicular anymore).

I measured the turning angle between left and right obstruction: 11°.

A full frame lens corner to corner at 250mm focal length covers 9.9°.

As soon as the exit pupil becomes obstructed you'll see the corners darken. As soon as the exit pupil blacks out you'll see black corners (happens at 26°). Half way in between, you lost 50% of the exit pupil or 1 EV in the corners. What I see in the posted images is 6 EV vignetting!!. Which should happen at 25° or more than a medium format image circle only! I am not convinced that the posted sample shots are from the 60-250mm. After all, film carries no EXIFs, errors are likely.

Therefore, I'll say for the time being that there is zero vignetting on FF except for the obvious cos^4 term. 11° is so close to 9.9° that I am tempted to say it was designed to cover the FF image circle ...


And my resolution test of the 60-250 is still pending

[vespats]

any news on the 60-250?

[falconeye]

any news on the 60-250?

The item just got bumped 5 positions up on my to do list (still not on top though )

[jsherman999]

.

Falk, great idea for a thread, very useful.

I can show some examples from the Tokina 12-24 f4 on a FF DSLR (D700) - basically the same thing you'd see with the DA 12-24 on film (same lens, sans coatings, maybe.)


.
12-24 @ 12mm

12-24 @ 15mm

12-24 @ 18mm

12-24 @ 19mm




Incidentally, the $199 Nikon 35 1.8DX - supposedly an APS-C only (DX) lens, works nicely on FF, as long as you're not shooting near infinity:


f/5, ISO 1250:


f/2.8, ISO 2000:


f/2.8, ISO 640:

[falconeye]

I can show some examples from the Tokina 12-24 f4 on a FF DSLR (D700) - basically the same thing you'd see with the DA 12-24 on film (same lens, sans coatings, maybe.)

jsherman, great idea to make reference to lens versions for bodies which have FF versions available. This could help fill the gaps.

As far as your valuable sample images are concerned: Is this with or without the lens hood? It looks like the vignetting is caused by a lens hood with a rectangular opening.

[falconeye]

Pentax has confirmed the DA*300/4 to be full frame.

The following is the patent filed by Pentax describing the DA*300 lens design: DA* 300

One is learning that the DA*300 is 290mm f/4.1 and Table1 applies a crop factor of 1.00. It isn't the FA*300/4.5 as the patent describes an 8 element in 6 groups lens. The FA*300 has 9 elements, the A*300 has 8 elements but 7 groups. And the original patent is from April 2007, a year before the DA*300 was released.

Table1 gives angle of view and focal length and from that, one can compute the image circle which yields the crop factor. 1.00 is the computed value from the patent. Some other Pentax patents yield 1.52-1.54 when doing the same.

So, we now may officially learn from Pentax that the DA*300/4 is a full frame lens.

I updated the opening post of this thread accordingly.
(I am still giving it an "++" rating because there is slightly better performance in the APS-C corners compared to FF. Probably true for all FF lenses though.)

[falconeye]

Pentax has confirmed the DA*60-250/4 to be full frame.

The following is the patent filed by Pentax describing the DA*60-250 lens design: DA* 60-250mm f/4

The patent for the DA* 60-250/4 describes several versions, like
61.5 - 243mm f/4.1 or 56.1 - 243mm f/4.1.

The crop factor in all versions is ~0.98/1.03/1.02 at wide/medium/tele zoom.

And no, 0.98 doesn't mean it vignettes. It is just rounding errors when converting angle of view to crop factor.


So, this is the official confirmation from Pentax that the DA*60-250/4 lens is a full frame lens indeed.


I updated the opening post of this thread accordingly.
(I am giving it a "++" rating which is temporary until it is tested.)

[Class A]

Great detective work, Falk!