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06-22-2019, 08:30 AM   #1
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IRIX 150 macro vs D-FA 100 WR macro ?

Recently looking back at the IRIX 150 macro. There is a thread about the announcement of the IRIX150 but it wasn't available for purchase at that time. Now the IRIX150 is available for purchase. Checked-out user review here (3 reviews). The price for both lenses are close now (approx. $600). IRIX 150 isn't AF, but it is 150mm giving a little more subject distance at 1:1 mag. I suppose. But some say that the IRIX 150 isn't sharp wide open. How does the IRIX 150mm compares to the Pentax D-FA 100 macro sharpness wise?

06-22-2019, 08:43 AM   #2
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This isn't exactly an apples-to-apples comparison, but Lenstip has reviewed both lenses and in their experience the Pentax is somewhat sharper wide open.

Irix 150 mm f/2.8 MACRO 1:1 Dragonfly review - Image resolution - LensTip.com

Pentax smc D FA 100 mm f/2.8 Macro WR review - Image resolution - LensTip.com
06-22-2019, 08:53 AM   #3
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the dfa is under $400 now


Pentax D-FA 100mm f/2.8 Macro WR AF Lens with Hood #21910 -USA- 21910

i wrote irix with the intention of doing an exhausting review against the sigma 180 and dfa 100, but the us division had no response. at 1:1, the 100mm is better... easier to use flash because subject is closer(less light needed) and lens is more compact (less in the way of the flash). for closer focusing/filling the frame with a snake's head or a dragonfly (closer than the da 300mm can get) with natural light, i use the sigma 180 every time. at 1:1 or very close to it, i use manual focus... in every other situation i use af. my favorite macro lens is the sigma 70mm... perhaps because of it's non-macro qualities.
06-22-2019, 09:21 AM   #4
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For macro use, one wouldn't normally use either lens wide open at 1:1 magnification. And AF doesn't matter at 1:1 either, you probably will need a tripod to control composition and focus.

But I also use my 100 wr as a general medium tele on apsc, and I like that it's sharp even at f2.8 and it has AF edit: and half the weight of the irix, apparently


Last edited by aaacb; 06-22-2019 at 09:29 AM.
06-22-2019, 09:25 AM - 1 Like   #5
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QuoteOriginally posted by biz-engineer Quote
IRIX 150 isn't AF, but it is 150mm giving a little more subject distance at 1:1 mag.
Working distance (not the same as MFD) is a huge concern, but just as important might be actually doing manual focus with either lens for your preferred close-up and non-close-up subjects* (AF only being a consideration for non-close stuff) and that matter of bulk, particularly when combined with stuff like focus rails.** There is also the question of the aperture ring, should you have the desire to up your game with extension rings or bellows.


Steve

* My Tamron 90/2.8 (72B) is beastly in regards to manual focus at distances greater than about 1.3m. BTW, remember that the Irix is internal focus and has less working distance at greater magnifications (~160mm off the barrel front at 1:1) than might be expected, offsetting the focal length advantage over the D FA 100 somewhat.

** At close to 1:1, it is easier to focus the full kit than to attempt with the focus ring.

Last edited by stevebrot; 06-22-2019 at 10:53 AM. Reason: accuracy
06-22-2019, 11:25 AM   #6
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1:1 is the same whatever the focal length. The only thing changing is the distance at which it's achieved and the field of view of the background.
The 100 macro is AF and WR. For non-macro I prefer the Sigma 70, which has great renditioning of out of focus but, in my bag day after day, it's the 100 macro. IN fact the 100 macro was selected because it's the same field of view on aa K-1 as the Sigma 70 on a K-3. I discovered I liked that field of view.

I think the wife and I would both enjoy the 200 ƒ4 macro, but it's expensive. We both use macro lenses as walk arounds a good percentage of the time. We have 50, 70, 90 and 100 covered in macro focal lengths.
06-22-2019, 01:21 PM - 1 Like   #7
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Due to the internal focusing of the IRIX its focal length decreases when approaching the subject. At 1:1 it's about 120mm effective. Thus the focal length advantage shrinks at higher scale. Adding to this the compactness of the Pentax 100mm, its better performance wide open, the AF and focus shift I know what I would recommend...

But the IRIX isn't bad at all and is a pleasure to use. And after all even the little difference of focal length at 1:1 will help a lot regarding the flight distance of insects for example.
06-22-2019, 01:42 PM - 1 Like   #8
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I am not sure why macro and af is soo looked down on. With my sigma 70 it is extremely accurate. I prefer to use it and allow my left hand to really stabilize the camera because of the weird angles I have to be for most "in the wild" macro shots. My flash is also off balance for position. Just breathing and pushing the shutter can move the focus extremely in macro.

06-22-2019, 02:37 PM   #9
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QuoteOriginally posted by forest_bear59 Quote
Due to the internal focusing of the IRIX its focal length decreases when approaching the subject. At 1:1 it's about 120mm effective. Thus the focal length advantage shrinks at higher scale. Adding to this the compactness of the Pentax 100mm, its better performance wide open, the AF and focus shift I know what I would recommend...

But the IRIX isn't bad at all and is a pleasure to use. And after all even the little difference of focal length at 1:1 will help a lot regarding the flight distance of insects for example.
This is an excellent point. According to the Lens Database, the MFD of the Pentax is 30 cm and the Irix is 34 cm.
06-22-2019, 04:35 PM - 3 Likes   #10
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QuoteOriginally posted by luftfluss Quote
This is an excellent point. According to the Lens Database, the MFD of the Pentax is 30 cm and the Irix is 34 cm.
MFD is the distance from focal plane to subject. Working distance (the space between subject and end of lens) would be:
MFD - (flange focal distance + lens length at MFD)
Even so, the two lenses are close to the same length at MFD, so the working distance consideration is minor.


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06-22-2019, 04:39 PM - 1 Like   #11
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Although it is true that the IRIX has a 20 cm working distance that is 43% farther from a skittish critter compared to the DFA 100/2.8's 14 cm working distance, The 77mm filter size of the IRIX makes the lens' front 57% larger than the 49 mm filter size front of the Pentax lens. From the critter's PoV, the front of the IRIX will look visually larger even if it is farther away.

The other downside of the longer FL is the need for more extension tube/bellow length to get to higher magnification. Getting to 2:1 with the IRIX requires 150 mm of extension. Getting to 2:1 with the Pentax requires only 100 mm of extension.
06-22-2019, 06:16 PM - 3 Likes   #12
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QuoteOriginally posted by photoptimist Quote
From the critter's PoV, the front of the IRIX will look visually larger
Eeeek!

Questions regarding macro gear usually come down to factors that might be deal breakers and what those might be depends a lot on choice of subject, intended approach, and whether the gear will be used for tasks other than macro. The D FA 100/2.8 Macro WR is an impressive tool with an established optical heritage in a compact and well-made package. The Irix 150/2.8 offers similar optical performance with manual focus in a well-made package. It would appear that price might be the major determining factor. However, I suspect that the devils found in the details will not show themselves until the third or fourth user session.

This short list is not based on personal experience with either lens (both are attractive to me, truth be known), but reflects the points of pain I have experienced doing close-up and macro work:
  • Hood? There is a strong case for hood use when doing flash work with macro. The D FA 100 extends within its hood which contributes 6cm bring the overall length to 14 cm regardless of subject distance. The Irix has a hood which I estimate adds an additional 5 cm regardless of subject distance. Yes, the matter of working distance (again)...
  • Total bulk including flash solution (on-camera, attached to camera rig, or off-rig)
  • Lighting...lighting...lighting...
  • On or off-tripod?
  • AF as a rule vs. MF as a rule vs. fixed focus (CIF, proximity trigger, etc.)
  • Higher than 1X magnification? (Raynox will only go to 67mm filter size...bellows and most extension tubes require aperture ring...and so on...)
  • Viewfinder dimming implications
  • Use at magnifications less than 0.3X?
While we can give our opinions on threads like this, there is no way to anticipate how the lens might be used. There is a reason why I have extension tubes, bellows, and three dedicated macro lenses (50mm, 90mm and 105mm). None was or is pain-free. I would really benefit from a focus rail too, truth be told, but there is likely a demon their too.

I wish @biz_engineer my best in making a good decision


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06-22-2019, 08:03 PM - 2 Likes   #13
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QuoteOriginally posted by swanlefitte Quote
I am not sure why macro and af is soo looked down on. With my sigma 70 it is extremely accurate. I prefer to use it and allow my left hand to really stabilize the camera because of the weird angles I have to be for most "in the wild" macro shots. My flash is also off balance for position. Just breathing and pushing the shutter can move the focus extremely in macro.
I wouldn't say that "macro and af is soo looked down on", it's simply that many of us find that focusing manually* is better for precise focusing on tiny subjects. I actually impress myself with being able to make such minute movements to obtain the focus point I desire.




Also, sometimes the AF noise - or maybe it's the sudden focusing motion of the lens - disturbs said subject.

And sometimes my method is completely different. There are times I'll hold the camera at arm's length and compose through the LCD and use an AF lens that's capable of close focus... because I feel at the time that is the best (or only) way for me to get the shot.





The important thing is to find methods that work for you. I try not only to control my own equipment and technique, but to consider my (usually mobile) subjects, learn what they are willing to tolerate and how best to work with them.



* I'm in agreement with @stevebrot in that I find it easier to move the full kit rather than turn the focus ring as I approach 1:1 magnification.
06-22-2019, 10:10 PM   #14
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I had the D-FA 100 macro WR with the K3, as complement to the Tamron 17-50 2.8 and HD 1.4x TC (D-FA 100 WR w/wo TC was small to carry in the bag in case I wanted macro or more than 50mm for landscape: in the camera bag I could have 17-50, 70mm (50+TC), 100, 140 (100+TC). Then the K1 changed that situation. I sold the K3 to fund the K1. With the K1 , I found the 1:1 magnification not so great on the K1 unless using crop mode (15Mp instead of 24Mp of K3), and especially the lack of aperture ring on the D-FA100 WR was a problem to set the lens aperture if using extension tubes. As I was looking to use a 85 1.4 lens on the K1, and more working distance for macro, I sold my D-FA 100 macro WR, to bought a Samyang 85 1.4 and bought a Marumi DHG Achromat Macro 330 / 77mm close-up lens (based on some good online reviews) hoping to transform my D-DFA 70-200 into a 200mm macro lens. But.. I end-up not using the Samyang 85 1.4 because it isn't that sharp even stopped down (has focus shift => DoF preview to improve subject focus). And the D-FA 70-200 macro conversion happens to be tricky to use such as setting the focus near infinity, moving the camera back and forth to achieve focus, and fine tuning focus with DoF preview, and yet not getting crisp macro images. So I don't use the Marumi DHG front lens anymore. That's why I was thinking to get a D-FA 100 WR again.

Now I saw the IRIX 150mm with potentially larger distance to subject. So I read: min focusing distance for D-FA 100 WR: 30cm. Min focusing distance for the IRIX 150 34cm. Min focusing distance is from the focal plane. Ahhhr and the IRIX doesn't have an aperture ring !

Last edited by biz-engineer; 06-22-2019 at 10:21 PM.
06-23-2019, 12:20 AM - 2 Likes   #15
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QuoteOriginally posted by biz-engineer Quote
That's why I was thinking to get a D-FA 100 WR again.
Did you notice @Luftluss stuff a few posts above? He does some pretty amazing work with fairly simple gear. The hoverfly was done with a K-S2 mated to an '80s vintage Tamron 90/2.5 Macro (52BB) + Raynox DCR 150. The Raynox provided a magnification boost over the Tamron's native 0.5X without f-stop penalty or loss of DOF*. One could probably buy the full kit (camera + glass) for the price of an Irix 150.

I don't do bugs, but am currently enamored of an '80s vintage Dine 105/2.8 in KA mount** that sort of fell into my lap in like-new condition for $100 USD (Thank you, Jay) on the PF Marketplace. The Dine is old-school to be sure, but is a cult classic with no faults that I have determined other than weight (638gm including caps).*** MFD is about 35cm at a maximum length of 17cm at 1.0X magnification. The fifth photo I took with the lens was "explored" on Flickr Friday with 47,000+ hits at present. Mate one to a Raynox for use on your K-1.


Steve

* ...and probably without sacrifice of the 55BB's 39 cm MFD

** Made by Kino Precision and also sold labeled as Kiron 105/2.8, Rikenon 105/2.8, and Vivitar S1 105/2.5, to name a few.

*** It might also show mild purple fringing/LoCA at some focus distances and light, though I have not fully characterized the behavior.

Last edited by stevebrot; 06-23-2019 at 01:10 AM.
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