Irix 150/2.8 review at Ephotozine

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RemcoR Senior Member • Posts: 1,199
Irix 150/2.8 review at Ephotozine
2

https://www.ephotozine.com/article/irix-150mm-f-2-8-macro-1-1-dragonfly-review-33078

RemcoR

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miles green
miles green Veteran Member • Posts: 7,093
Re: Irix 150/2.8 review at Ephotozine

Interesting.

For us not having AF is quite OK as we have CIF, same as it being unstabilized.

But it breathes quite a lot, check out the minimal focus distances:

Irix 150mm: 34.5 cm

Pentax 100mm: 30cm

So at 1:1 magnification, it's more like a 110mm lens. 

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MightyMike Forum Pro • Posts: 39,346
Re: Irix 150/2.8 review at Ephotozine
5

miles green wrote:

Interesting.

For us not having AF is quite OK as we have CIF, same as it being unstabilized.

But it breathes quite a lot, check out the minimal focus distances:

Irix 150mm: 34.5 cm

Pentax 100mm: 30cm

So at 1:1 magnification, it's more like a 110mm lens.

Most if not all IF lenses do focus breath a lot, however all macros focus breath a lot at close focusing distances. I'm sure I've seen the patent of the F 100mm F2.8 Macro and by 1:1 its in the 70-78mm range, I don't recall the exact range as it was some time ago. So its rather more like 81-90mm at 1:1. That said pay attention to the working distance rather than the minimum focusing distance.

The F 100mm F2.8 has a 30.6cm MFD but an approx. 11.6cm working distance, hood built in

The DFA 100mm F2.8 WR has a 30.3cm MFD but an approx. 17.3cm working distance without the hood

The Irix 150 has a 34.5cm MFD but an approx. 17.7cm working distance without the hood

I suppose not much better in that regard though.

As I scan over the review I'm disappointed by the resolution, If we were to use the decency level definition from lenstip where approx. F16 resolution is decent, not bad but not good either then F2.8 leaves something to be desired, However after viewing well over 100 resolution charts from Ephotozine I find many of them are either overly optimistic or don't match my subjective experience with a certain lens (better and worse) They must just have a different methodology for this than other websites.

Nothing else worth mentioning as all other things are good, great or expected.

This lens still has my attention as an upgrade however I want to see more reviews and I'm still waiting on the Venus 100mm F2.8 2:1 APO Macro which may win the evaluation.

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Mike from Canada
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tex Veteran Member • Posts: 7,857
I regard you as something of a K-mount expert....

so, I'm curious about your last sentences.  What's wrong in your opinion with the DFA 100?

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OP RemcoR Senior Member • Posts: 1,199
Re: Irix 150/2.8 review at Ephotozine

MightyMike wrote:

miles green wrote:

Interesting.

For us not having AF is quite OK as we have CIF, same as it being unstabilized.

But it breathes quite a lot, check out the minimal focus distances:

Irix 150mm: 34.5 cm

Pentax 100mm: 30cm

So at 1:1 magnification, it's more like a 110mm lens.

Most if not all IF lenses do focus breath a lot, however all macros focus breath a lot at close focusing distances. I'm sure I've seen the patent of the F 100mm F2.8 Macro and by 1:1 its in the 70-78mm range, I don't recall the exact range as it was some time ago. So its rather more like 81-90mm at 1:1. That said pay attention to the working distance rather than the minimum focusing distance.

The F 100mm F2.8 has a 30.6cm MFD but an approx. 11.6cm working distance, hood built in

The DFA 100mm F2.8 WR has a 30.3cm MFD but an approx. 17.3cm working distance without the hood

The Irix 150 has a 34.5cm MFD but an approx. 17.7cm working distance without the hood

I suppose not much better in that regard though.

As I scan over the review I'm disappointed by the resolution, If we were to use the decency level definition from lenstip where approx. F16 resolution is decent, not bad but not good either then F2.8 leaves something to be desired, However after viewing well over 100 resolution charts from Ephotozine I find many of them are either overly optimistic or don't match my subjective experience with a certain lens (better and worse) They must just have a different methodology for this than other websites.

Nothing else worth mentioning as all other things are good, great or expected.

This lens still has my attention as an upgrade however I want to see more reviews and I'm still waiting on the Venus 100mm F2.8 2:1 APO Macro which may win the evaluation.

Hi Mike,

I excluded the rather typical review of the "much loved" Ken Rockwell. Nice pics of the box in came in though and perhaps some other shots might be of interest.

https://kenrockwell.com/tech/irix/150mm.htm

RemcoR

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Pentax K-5
Samyang 14mm f/2.8 IF ED UMC Aspherical
Pentax FA 35mm F2 AL
Carl Zeiss Vario-Sonnar T* 35-70mm F3.4 Macro
Carl Zeiss Planar T* 50mm F1.7 Contax
Carl Zeiss Planar T* 85mm F1.4 ZK
Carl Zeiss Distagon T* 21mm F2.8
https://www.flickr.com/photos/126796413@N03/
http://www.pentaxphotogallery.com/RemcoRog

miles green
miles green Veteran Member • Posts: 7,093
Re: Irix 150/2.8 review at Ephotozine

MightyMike wrote:

miles green wrote:

Interesting.

For us not having AF is quite OK as we have CIF, same as it being unstabilized.

But it breathes quite a lot, check out the minimal focus distances:

Irix 150mm: 34.5 cm

Pentax 100mm: 30cm

So at 1:1 magnification, it's more like a 110mm lens.

Most if not all IF lenses do focus breath a lot, however all macros focus breath a lot at close focusing distances. I'm sure I've seen the patent of the F 100mm F2.8 Macro and by 1:1 its in the 70-78mm range, I don't recall the exact range as it was some time ago. So its rather more like 81-90mm at 1:1. That said pay attention to the working distance rather than the minimum focusing distance.

The F 100mm F2.8 has a 30.6cm MFD but an approx. 11.6cm working distance, hood built in

The DFA 100mm F2.8 WR has a 30.3cm MFD but an approx. 17.3cm working distance without the hood

The Irix 150 has a 34.5cm MFD but an approx. 17.7cm working distance without the hood

I suppose not much better in that regard though.

My point exactly!

As I scan over the review I'm disappointed by the resolution, If we were to use the decency level definition from lenstip where approx. F16 resolution is decent, not bad but not good either then F2.8 leaves something to be desired, However after viewing well over 100 resolution charts from Ephotozine I find many of them are either overly optimistic or don't match my subjective experience with a certain lens (better and worse) They must just have a different methodology for this than other websites.

Nothing else worth mentioning as all other things are good, great or expected.

This lens still has my attention as an upgrade however I want to see more reviews and I'm still waiting on the Venus 100mm F2.8 2:1 APO Macro which may win the evaluation.

A true APO at 100mm would be something! Venus keep making lenses hat really grab my attention, i'll have to get one sometime.

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Miles Green
Pentaxian since 1997!
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N.B. All my images are protected by Copyright

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MightyMike Forum Pro • Posts: 39,346
Re: I regard you as something of a K-mount expert....

tex wrote:

so, I'm curious about your last sentences. What's wrong in your opinion with the DFA 100?

Sorry for the delay, I've been away for a week. Yes I have the F 100mm F2.8, FA 100mm F2.8, DFA 100mm F2.8 WR, the F and FA are identical and the DFA is very very similar. They are all very good but also there is nothing unique or special about them (aside from the WR). Now the FA's and DFA WR I bought for the purpose of resale, its what I do, they're worth more to me as cash than an upgrade/side grade. The Venus 100mm F2.8 APO 2:1 macro has some advantages and extras with the loss of AF and therefore worthy of consideration as an upgrade path, the Irix 150, was worthy of consideration but I'm not as sold on it as I could be.

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Mike from Canada
"I am not a great photographer! God is a great creator! All I do is capture His creation with the tools He has provided me."
'I like to think so far outside the box that it would require a telephoto lens just to see the box!' ~ 'My Quote :)'
http://www.michaelfastphotography.com/galleries/VP-BDI_3a.jpg
http://www.airliners.net/user/SpeEedy/profile/photos?sortBy=photoFavoriteCount

tex Veteran Member • Posts: 7,857
Thanks! /nt
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"Photography is the product of complete alienation" Marcel Proust
"I would like to see photography make people despise painting until something else will make photography unbearable." Marcel Duchamp

 tex's gear list:tex's gear list
Pentax 645Z Pentax K-1 Pentax K-1 II Ricoh Theta V Pentax smc FA 77mm 1.8 Limited +29 more
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