Irix 150mm Macro


Lubbyman

Link Posted 15/02/2019 - 11:29
With all the excitement about the new Pentax lenses, has anyone noticed the new Irix 150mm macro?

I’ve acquired one because of niggling limitations of my film-era Sigma 105mm macro: not WR, fairly short working distance at 1:1 magnification and big extension when focussing. Buying a newly released lens is not usually my thing, but with a non-UK purchase the only current option and goodness knows what going to happen at the end of March, it seemed sensible to go for it now. John Riley’s ePhotozine review (not with a Pentax) appeared just in time to be a sanity check before pressing the ’buy’ button. It didn’t put me off, so the button was pressed. Here are some first thoughts.

The review is spot on. The lens seems well built, has all that a macro lens needs, handles well and sits nicely on a K3. Colours seem more accurate than the Sigma, presumably because of more modern lens coatings. It’s over twice the weight of the Sigma, but strangely doesn't feel like it on the camera. Lack of AF is not an issue for me, I never use it for macro. No front extension when focussing is a pleasure and WR is taken on trust – I am not going to run it under a tap to check it out!

Working distance is not so straightforward. At minimum focus distance (1:1 magnification), front of lens to subject is about 18cm for the Irix, 12cm for the Sigma (my measurements). However, the front element of the Sigma is well set back from the front of the lens so I rarely use a lens hood. The front element of the Irix is not set back so its lens hood may be needed. Minimum working distance from front of hood to subject is about the same as for the Sigma without lens hood. Of course, as distance to subject increases and magnification decreases, the presence of the Irix lens hood becomes less significant.

The Irix now sits next to the Sigma on my lens shelf. Time will tell which one I reach for most. But all in all, the Irix seems to be a worthwhile addition to the macro repertoire for Pentax.

Steve
PS: My first post in 10 years. Something vaguely useful to say at last!

Mike-P

Link Posted 15/02/2019 - 12:53
Nice second post Would like to see some pictures from it

I have the Sigma 180mm f/3.5 macro and was not sure whether to sell it and buy the Irix but the lack of AF (not that I really use it for macro) and the fact you can't alter the aperture via the body ( correct me if I'm wrong but it has to be done on the lens?) has put me off slightly.

Where are you in Dorset btw ?
No equipment list here but thanks for taking an interest. My Flickr

derek897

Link Posted 15/02/2019 - 15:04
Nice post, (fantastic 2nd post) makes some interesting points.
I have long lusted over Mike's lovely 180mm macro, but the cost is rather prohibitive, (for me) .
When I saw the initial preview of the irix I thought, this might be worth going for.
But then the bombshell, for me anyway, there would be no aperture ring, strange decision to do that to a macro lens, I do most of my macro shooting with bellows , so I knew the bellows were out. But then I had a thought, ext tubes with contacts should work and still allow the changing of aperture via camera, game on again. Then I read a review on the US forum that said ext tubes won't work either.
Game called off again.
I did ask the question on the forum but to be honest I didn't really get the why they won't work.
So hopefully seeing as you have one you can help me out here.
If the aperture is not controlled via camera body. Nor via aperture ring, just how do you change the aperture ?
Have you tried the lens with ext tubes ?
I too use a sigma 105mm for my macro shooting at present, although there is a Lester dine 105mm on its way to me as I write.
I would love a longer fl, so am rather keen to hear your answer if you can help clarify things.

Cheers
Derek
I know what i like, If not always why.

Algernon

Link Posted 15/02/2019 - 15:29
Due to focus breathing this lens doesn't give you any more working distance than the Pentax 100mm WA when you put a hood on. Also check the point about f/16 resolution in this post....

https://www.dpreview.com/forums/thread/4366642

--
Half Man... Half Pentax ... Half Cucumber

Pentax K-1 + K-5 and some other stuff

Algi

Mike-P

Link Posted 15/02/2019 - 15:49
Algernon wrote:
Due to focus breathing this lens doesn't give you any more working distance than the Pentax 100mm WA when you put a hood on.

So all in all a bit pointless then

I didn't look into it that much but presumed it had an aperture ring as it is missing the contacts to do it in body.
No equipment list here but thanks for taking an interest. My Flickr

Jonathan-Mac

Link Posted 15/02/2019 - 17:30
At the very least it's good news that third party lens manufacturers are supporting Pentax.
Pentax hybrid user - Digital K3 & K200D, film 645 and 35mm SLR and Pentax (&other) lenses adapted to Fuji X digital
Fan of DA limited and old manual lenses

Mike-P

Link Posted 15/02/2019 - 17:43
Jonathan-Mac wrote:
At the very least it's good news that third party lens manufacturers are supporting Pentax.

Indeed it is as they are very far and few between these days.
No equipment list here but thanks for taking an interest. My Flickr

BarryE

Link Posted 15/02/2019 - 17:56
I've an Irix 15mm which I use on a K-1 and it's excellent. The arrival of the 150mm made me consider Irix again. I have a DFA 100mm, but I'm looking for more reach, but not at macro distances. All the reviews and comments I've read are about the Irix for macro work, but what is it like for non-macro - up to infinity ? I like using the DFA 100 to pick out elements in a landscape, but there are times when more reach would be nice and the 100 does flare a little. So I'm trying to find out what the Irix is like for non-macro and also when shooting into bright light.
Many thanks for any clues or pointers ...

Algernon

Link Posted 15/02/2019 - 18:22
A MF macro lens is a pig for normal use. The distance scale has very little space as you approach INF.

--
Half Man... Half Pentax ... Half Cucumber

Pentax K-1 + K-5 and some other stuff

Algi

derek897

Link Posted 15/02/2019 - 19:19
I don't use a hood as I have my own built into my ring flash diffuser.
I'd like to see a sample shot with irix at min focus distance and with the 100mm at min focus distance. At any aperture. Of same subject.
I have never used the distance scale on any lens, so no loss or gain for me.
Still don't know how you change aperture
I know what i like, If not always why.

Lubbyman

Link Posted 16/02/2019 - 21:55
Not much spare time at the moment due to sick wife, visitors, work etc. - the usual stuff of life. Pictures will have to come later. But some quick replies now.
- Aperture control is like any Pentax lens that doesn't have an aperture ring, it's done from the camera body in the usual way. If you need an aperture ring for what you want to do, the Irix isn't for you.
- The contacts on the lens mount are what you would expect for a Pentax lens. A lever opens and closes the aperture. The pictures on the Irix website are not the Pentax version.
- I don't have any extension tubes so can't check them out. I can't see why tubes wouldn't work with the Irix if they work with other lenses without an aperture ring. I've occasionally used the Pentax 1.4 TC with the old Sigma. Trying it with the Irix is on my list of things to do when time permits.
- I've not tried the Irix at non-macro distances yet other than a couple of shots to check it worked and see what it felt like. Again, it's on my list of things to do when time permits.
- Algi is, of course, right about the distance scale having very little space as you approach inf. But although the angle of turn between 1m and inf is about the same on the Irix as on the old Sigma, the barrel diameter is much bigger on the Irix and focussing seems smoother (at least with my hands). So I wouldn't be surprised if MF at longer distances is easier on the Irix, although still more difficult than with a non-macro 150mm.
- I'll try shooting into the sun when it puts in an appearance. Currently doing its best to hide behind cloud whenever I've got a free moment. I too am interested in finding out when the lens hood is really needed. The ePhotozine review includes a picture with a bright light at the top edge and the statement "Flare resistance is also very impressive and in fact, no evidence of flare is to be found.". So I'm hopeful.
- I've got some graphs of magnification vs. distance from front of lens to subject, for both the Irix and old Sigma. Currently sitting in a spreadsheet. I'll post them when I can work out how to put them in a format that can be posted.
- For Mike-P - I'm in the County Town. For those who don't know the County Town of Dorset - shame on you!!

Incidentally, the ePhotozine review says that focusing is down to 0.345m or 0.92 feet. That should be 1.13 ft. The distance on the lens is correct, the incorrect number presumably comes from copying what is on the Irix website. If you can't trust an ePhotozine reviewer, who can you trust...??

Steve

derek897

Link Posted 17/02/2019 - 00:13
Cheers Steve, plenty of useful info there,
Thanks for clarifying the aperture control, it made no sense that it couldn't be controlled via camera. Now it does rule out the bellows but maybe not the tubes with contacts.
It's hard to see why it wouldn't work.
Looking forward to further updates.
Hope the missus is better soon.

Derek
I know what i like, If not always why.

Lubbyman

Link Posted 18/02/2019 - 10:18
As promised, here's a graph of magnification vs working distance for the Irix 150 and Sigma 105. Strictly speaking, it's magnification relative to size at minimum focus distance. I've assumed for each lenses that magnification at its minimum focus distance is 1:1 as manufacturers claim. All done using a low tech, quick and dirty method involving a metre rule and a large bolt, so not high precision measurements, but good enough to show what's happening for those who like to know such things.




Photos still to come. Just recovering from weekend visit by daughter, 3 year old granddaughter, some pink rabbits and a couple of unicorns. Photography had to take 2nd place to entertaining the child.

Steve

Lubbyman

Link Posted 18/02/2019 - 11:30
And now for some pictures.

Catkins at f2.8, f5.6 and f11. Not 1:1, just a convenient subject for checking effect of varying aperture. Focussed on front of nearest catkin, background a long distance behind (relatively). Outdoors in shade. A still day but can't guarantee the catkins were perfectly still. K3 + Irix 150mm, tripod + 2 sec delay. DNG files, slight sharpening at raw, resize to 800px then sharpen (USM).

f2.8




f5.6




f11




Steve

Lubbyman

Link Posted 19/02/2019 - 23:44
This one for Barry E. Here are a few non-macro pictures, focus ranging from about 20 yards to about 3/4 mile. Done while walking the dog, K3 held by one hand, other hand holding dog on lead and focussing with a couple of fingers, so challenging to say the least! SR on. Aperture and ISO chosen to give exposure time less than 1/(1.5f). Viewfinder with OME53 magnifying eyecup. Minimal processing of DNG files, slight sharpening of raw then sharpen (USM) after resizing to 1200px horizontal.

Focussing was easier than I expected, the focus ring rotates smoothly and precisely with a reasonable amount of 'resistance'. The short distance on the focus ring between near distance and infinity means you've got to be careful. But it's possible and should be even easier with a tripod and live view.

1. Focus on gate, guess about 20 yards away




2. Focus on gate, guess about 150 yards away




3. Focus on swans, guess about 3-400 yards away




4. Focus on pole in centre, guess about 3/4 mile away




Make of them what you will!

Steve
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