SK 35&55mm/IQ180 vs Pentax 28-45mm/645Z test and A7RII 90mm macro..Must Read!

[Dan Santoso]

Hi All,

I just got back from a trip in China. A friend in our group has Pentax 645Z and we did a test comparison for fun with my IQ 180. I was very surprised how the pentax performs. For a system that cost 1/5 less than the IQ, it performs very similar, with lighter body and lens, manual focus magnification and focusing peak, weather sealed lens and body, and amazing high ISO...looks very attractive all of sudden.

I bought the SK 35MM blue ring prior to the trip. I thought this lens will kick ***, being the latest offer from Phase one and because it was advertised as ready for 100MP and beyond...so i thought let's do a test vs the pentax 645Z with 28-45mm to see how good is the blue ring.

All camera on tripod with timer, same width frame. I was going to process both files with the same program but C1 does not support Pentax (make u wonder why...). So I convert the pentax to DNG and tweak a bit in adobe raw. IQ180 files was straight convert via C1. IQ180 files was downsized to pentax size.

All DNG and IIQ files can be downloaded @ ( will add more files later)
https://www.dropbox.com/sh/kdl9vdojochxb6n/AAAYn0Vva8FQyJVf-COyWHBIa?dl=0

For your enjoyment : (first full image from IQ180)






I was very surprised to see that the Pentax HD 28-45mm SR can hold to the SK35 Blue Ring. Image looks very similar with more pleasant color in IQ180. Color can be adjusted easy, the resolution in other hand can't be created in post.

The pentax is $1000 cheaper than SK 35MM and it is a zoom lens!! The mighty blue ring that goes beyond 100mp and ready to the future was expected to perform much better only to find itself shamefully almost identical to the zoom lens. Upon more testing against 55MM LS, I found the blue ring optically the same as the old generation LS. If phase one philosophy of blue ring only to provide better solid built, I am not impress!! Where are the qualities that belongs to "beyond 100MP and ready for the future", I am sure it is not the mechanism, electronically serialized and improve feel :ROTFL:

The one thing that I cant let go of phase one now is the capture one, I also like the focus mask to give hint of critical focus. I work in commercial and C1 is mandatory with the digital assistant. As the most expensive and the claim as the best in photography, I expect to see much more improvement from Phase One.

For those of you who only shoot landscape or first timer investor in MDF and you dont need C1 critically, I suggest the 645Z. It is much cheaper system with less weight, high iso and weather sealed that can rival the best phase one can offer. 2nd option will be Sony A7R II. The 90mm macro I test shows better result than SK 240 LS.

Here are test from 55LS







For the extra I throw a A7Rii with Sony 90 macro. I have been hearing about this amazing lens. Sony was converted with C1. All default values.

Test 1: not same width because i cant move back anymore with my IQ. Nevertheless it shows what this amazing Sony lens can do. IQ has finer details sure it is expected, but I dont think anyone expect Sony to have this level of details for 1/12 of the price of IQ




Test 2: Macro shots, still amazing Sony almost catch up to the SK



For those who have been wanting to get A7RII don't hesitate anymore. I'm assure you it is the best 35mm full frame available period

-Dan

 

[Paul2660]

Hi Dan,

Thanks for the posting.

The real test to me would be keeping the IQ180 at 100% and uprising the Pentax to the same size, as downsampling always tends to add both contrast and clarity at least with my experience. The fact that a Pentax @ 100% with 50MP looks similar to a IQ180 down sampled to almost 1/2 the resolution, well, 80MP vs 50 is not half but getting close tells me that you have a very good copy of the 35LS and the lens is doing what it's supposed to do. To my eyes, I don't think your 35mm will have any trouble with 100MP.

The Pentax is no slouch, but take the same Pentax files and uprez them to the same size as 80MP and see if they hold up. I don't think that they will as that is a pretty good stretch in resolution.

The IQ180 files also seem to have a bit more shadow life to them which surprised me, but that should be easy enough to change in post production.

But even looking at the IQ180 to Pentax in your examples, I see areas where the IQ180 still seems to have the edge,

Look for anywhere there is lettering on the buildings, the details of the actual bricks, the air conditioners on the builds and fine details in the greens.

Also in the tiles of the roof, the 35mm LS seems to have held a bit more hyperlocal distance as the foreground looks just a bit sharper.

Would these details show up in a web image, no, but would they show up in a print, hugely so, especially if you took the Pentax image to the same size as the IQ180 and then printed both out at 360ppi in LR or a similar program. But for this test, it would be interesting to see just the Pentax uprez'd to 300dpi to the same resolution as the IQ180 native at 300dpi.

I still feel that the SK35 is a Major step forward for Phase One, and I do hope when mine arrives, it shows the same excellent results are yours.

Sincerely
Paul

 

[Ken_R]

Zooming into the images the IQ180 file is much smoother (tones) with better color. The 645Z file looks a bit dull and flat and has quite a bit of texture (noise) that can be seen in areas with more uniform color / surface. Good, but not great.

 

[jagsiva]

The 35LS looks to be quite remarkable, closest one SLR wides have come to tech lenses yet.

 

[Kolor-Pikker]

Zooming into the images the IQ180 file is much smoother (tones) with better color. The 645Z file looks a bit dull and flat and has quite a bit of texture (noise) that can be seen in areas with more uniform color / surface. Good, but not great.

The tone/color difference can be attested to the difference between CCD and CMOS, having an extra few stops of DR tends to make things look terribly flat out of camera, but you can do crazy things with it. The 645D looked nicer OOC, but was far less flexible with exposure control than the Z, I suppose it depends on how much time you're willing to spend on dialing in the look you want.

Not sure what you mean about noise, at ISO100 and without any exposure push or recovery, the image appears smooth as glass. It's the closest I've ever seen a camera render a scene like computer graphics.

In any case, Pentax really knocked one out of the park with the 28-45mm, makes want to get it more every time I hear something new.

 

[Ken_R]

Here, It is pretty obvious:



Might be an issue with processing and/or the fact that the IQ180 image is downsampled quite a bit and that reduces apparent noise.

 

[Speedgraphic]

Not surprised to see this at all. When it comes down to it, Pentax makes remarkable glass and cameras. So does Phase and SK! They're all great. However, unless you need some of the P1 killer apps (leaf shutters, studio applications) you are throwing a lot of money their way for not a lot of return on quality. What most surprises me is that P1 or Hassy don't have a market competitor to the 645z. It doesn't have to be their flagship model but there should be something better than those ancient 40mp CCD cams. Just something that is great for location/wedding photographers. *shrug* If they want Pentax to have all that money, that's their call.

 

[algrove]

You should see the neg comments about the 645Z over on the Leica side "Re Leica SL (601)...Oct 20th" thread. I am exhausted.

http://www.getdpi.com/forum/leica/56286-leica-sl-601-oct-20th-5.html

 

[Paul2660]

Dan,

I took sometime and downloaded the two files. The Phase One appears to be a true raw, but I wasn't sure where how you created the Pentax dng? Is that straight from the camera? if so then C1 opens it OK, albeit with some color issues, mainly blues, or did you open it in LR and then export it out as a dng? The main reason I was curious, as if you exported out from LR, then the sharpening you had in LR would have been saved to the dng. But overall both files have a ton of detail. The Phase One IQ180 to me was easier to master overall colors and it seemed to have more reach in the shadows, not sure why, but to me it just did. Actually, your IQ180 does a very good job. Even the far lower right, where there is bamboo and a tree recovered with plenty of details, at iso 100, FAR better than my IQ260 would have done. The only area where I saw classic CCD noise/low details was in the lower left of the frame, where there is a sidewalk right above the river and a brick wall, here the 645z definitively wins since it was able to pull more details from the shadows, but your IQ180 is close and if you uprez'd the Pentax file to the output size of the Phase, it might be much closer.

Here are some crops, I hope that show enough but I have never liked on screen crops for comparisons. The colors have changed a bit, when converted to the web, but overall details still show I feel.


This is a shot from the upper left and I used it because you are pulling in the distant hillside, which has to be miles away and still the roof details in the middle foreground. To me, the Phase file shows a bit more details on the buildings but on the far hillside, the Phase is showing to me a lot more details on the trees, and the colors look better to me in the original. If you were to take the Pentax to the same resolution as the IQ180 native, then you are going to loose some more details on the far hillside. I also feel that for some reason the Phase One is showing more out of the roofs in this crop.











This is a shot of the buildings on the middle right and to me it's a toss up as the Pentax is pulling a bit cleaner image, (note in the white buildings), but I see more details in the grey bricks from Phase. Also the railings seem to stand out a bit better to me on the Phase One.













I only posted this one to show the details on the side street. Here you can see down the street very easily from the Phase One image but even with shadow recovery I really was not able to get as much from the Pentax, could have been a bit different lighting. The buildings in the background are about the same to me, but again the hills in the distance go to the Phase as there is better details and color to my eyes.


All of the crops were taken from C1 with both images viewed side by side at a 100% view with sharpening applied.

To me, the 35LS is doing a very good job. You were at F14 if I remember so there is possibly a bit of diffraction effecting the Phase One shot, but not much. Is the Pentax as good, well, sure it's close and in some cases as good, but again it's working on 30% less sensor so the edges of the shot from the Pentax should be a bit better. I can't remember the pitches of each sensor.

I sure would hold on to your IQ180 as it's getting really good results @ iso100.

Paul












This is taken from the right side middle and I used it to show the foliage. Here I preferred the Phase again, just liked the color and felt that there are just a bit more details coming from the Phase One.

 

[Paul2660]

Last note,

I wanted to add a side by side. Both files were a bit blown in the sky on the right, it was easy to me to even it out in C1 with a few adjustment layers. The Pentax sky never really got where I wanted it, but it might have something to do with the way C1 is reading the dng.



Paul

 

[Dan Santoso]

Hi Paul,

I convert Pentax RAW via DNG and open it in CS6 and adjust with adobe raw. I dont use C1 for Pentax.

Sure the color and background looks better in Phase one but at what cost? 5 times more expensive!!!

The IQ is also a full frame while the Pentax is not. The SK is a fixed lens while Pentax is zoom.

So if I were ask which one is the winner? I would say the Pentax for above reasons!

Phase one should be able to pull ahead much more from the Pentax given its price!!!

Last note,

I wanted to add a side by side. Both files were a bit blown in the sky on the right, it was easy to me to even it out in C1 with a few adjustment layers. The Pentax sky never really got where I wanted it, but it might have something to do with the way C1 is reading the dng.

View attachment 113490

Paul

 

[tsjanik]

I can't see the mentioned noise in the Pentax image, so I looked at the downloaded files. I still don't see it. Here are crops of the same portion of the building. The Pentax image is enlarged ( no up-rez, just bigger pixels) to fit the resolution of the Phase; the resolution difference is noticeable, but so is the contrast difference. Both opened in ACR.

 

[Dan Santoso]

Re: SK 35&55mm/IQ180 vs Pentax 28-45mm/645Z test and A7RII 90mm macro..Must Read!

I am sorry but the IQ will not be able to compete at all with noise vs the pentax.

Pentax can produces clean usable ISO 40,000. My IQ is screaming noise at ISO 400. No contest here!!!! I even sure Pentax will have better ISO than IQ 250/350.

I can't see the mentioned noise in the Pentax image, so I looked at the downloaded files. I still don't see it. Here are crops of the same portion of the building. The Pentax image is enlarged ( no up-rez, just bigger pixels) to fit the resolution of the Phase; the resolution difference is noticeable, but so is the contrast difference. Both opened in ACR.

 

[ErikKaffehr]

Re: SK 35&55mm/IQ180 vs Pentax 28-45mm/645Z test and A7RII 90mm macro..Must Read!

Hi,

Just a few observations:

• Both images were shot at f/14, which means that the sharpness is limited by diffraction.
• Both lenses seem very good out to the corner (I was checking lower right corner that has some good detail).
• Pentax 645D has clipping in the sky on the green channel while IQ 180 is about one stop below ETTR. So Pentax is overexposed and the IQ-180 could take one step more.
• I did my conversion in LR6 that supports both backs. I have some significant reservation about the demosaic part in Lightroom. I set noise reduction to zero on both.
• When viewing in Photoshop the Pentax 645Z image was upsized to IQ-180 dimensions.
• I would say the Pentax image was remarkably good. Even pixel peeping the differences were not that great. The part that Ken said was grainy was smooth on the Pentax in my conversion while the IQ-180 had some not really obtrusive noise

Interesting comparison and reasonably well made, I would say.

Best regards
Erik

I am sorry but the IQ will not be able to compete at all with noise vs the pentax.

Pentax can produces clean usable ISO 40,000. My IQ is screaming noise at ISO 400. No contest here!!!! I even sure Pentax will have better ISO than IQ 250/350.

 

[synn]

Hi Paul,

I convert Pentax RAW via DNG and open it in CS6 and adjust with adobe raw. I dont use C1 for Pentax.

Sure the color and background looks better in Phase one but at what cost? 5 times more expensive!!!

The IQ is also a full frame while the Pentax is not. The SK is a fixed lens while Pentax is zoom.

So if I were ask which one is the winner? I would say the Pentax for above reasons!

Phase one should be able to pull ahead much more from the Pentax given its price!!!

https://en.wikipedia.org/wiki/Diminishing_returns

 

[tjv]

While I could never afford to buy an IQ180 new–I own a Credo 60 that I bought used–there are many compelling reasons someone might prefer one over the Pentax. Price isn't one of those reasons, but for certain use cases it'd be worth it. In terms of this scenario, it clearly illustrates the law of diminishing returns for one type of work / shooting scenario. The Pentax seems an awesome camera. Brilliant, in fact.

 

[Kolor-Pikker]

While I could never afford to buy an IQ180 new–I own a Credo 60 that I bought used–there are many compelling reasons someone might prefer one over the Pentax. Price isn't one of those reasons, but for certain use cases it'd be worth it. In terms of this scenario, it clearly illustrates the law of diminishing returns for one type of work / shooting scenario. The Pentax seems an awesome camera. Brilliant, in fact.

And the fact that you get 28+35+45mm in one lens, with weather sealing and image stabilization... you could probably hold it down to 1/8th sec. I actually hope that the new zooms Pentax will release will also be optimized for this sensor size, then we'll have a killer set covering everything from 28-160mm in just three lenses.

Going back to the noise issue, I think it may have had to do something with being a demosaicing artifact, since it had a maze-like pattern to it. I double-checked with some of my own images, and here is a before/after of old image I posted here before:

And a 100% crop of where I think the worst of the noise is:

If I didn't add exposure or shadow recovery, this would be even less perceptible, not that it matters, since a pattern this fine will ultimately get lost in the surface texture of any print media... Which I think is the smoking gun we need, if someone prints these crops out for visual inspection, possibly even with third-party blind testing, I think we can all be happy that we use the best cameras on earth, whether or not you have or desire that last 5% of image quality.

Edit: and here is another crop of a different image where I used the legendary Sony +5 Stop Exposure Push™ - Not bad for shadows that are effectively ISO3200.

 

[Paul2660]

No doubt the 645z is appealing. I just noticed it is now 7K at BH Photo. I did not realize the body had come down from 8.4K.

Paul

 

[Pradeep]

Interesting comparison. I've owned the IQ180 (but not the 35LS) and now own the 645Z (but not the 28-45).

To my eyes, in the posted samples, the Phase files do look sharper and hence better if only resolution is compared.

Several points need to be understood in a comparison of this sort, IMHO.

1. Lens: More than the camera, I believe the lens is the key, especially if the sensors are both equally capable. I wonder how the Pentax would have performed say with the DFA 55 or DFA 90, both being modern prime lenses well suited to the digital medium, or if the two systems were compared with zooms of a similar range.

2. Ultimate objective: I may be wrong, but the final resting place of any image must be a print, whether on paper or aluminum or whatever. I doubt we are all happy to just have them sit on a hard drive or on a webserver. In the latter instance, nobody is going to look at the right lower corner at 100% etc. Hence the comparison is useless unless the final destination is taken into account. If it is a print, as I think it would be, then too, the differences at the 'usual' size would be minimal, as was shown so long ago by Michael Reichmann.

When I bought my Phase IQ180 I was told by all the enthusiasts present that the difference in print quality between Phase and a Canon DSLR would be visible at '8X10' size, a blatant untruth.

Having printed large (over 24X36) with Phase 180, Canon 1DX and now Pentax 645Z, I can tell you that unless you are 3 inches from the print or using a loupe, the difference is not noticeable at all at anything smaller than 20X30 and above that, the Pentax and Phase files are absolutely indistinguishable!

So a lot depends upon what you want to do with the images you shoot. Granted, you can 'crop into' a larger resolution file with greater ease but that is hardly the purpose of shooting with a high resolution camera to begin with.

3. Cost: This is the big issue I think with the OP as it was with me. I discovered that the value for me was not there, given my style of shooting and there were several major limitations to boot. However, this is a very subjective matter and for many the value is in the joy they get out of using the system and nobody can argue with that.

BTW, I also own the A7RII now and the superb Batis lenses and as I've said repeatedly, the combination of the Sony and the Batis 25 is just about the best IQ for the price and heft.

 

[jerome_m]

I think I have said this before: if you take two cameras, use the resolution of the lesser camera, make sure you use very good lenses at their sweet spot (f/11-f/16), make sure you have enough light to use relatively low isos, take a scene with relatively limited dynamic range, etc... you will find identical results between these two cameras, whatever are the two cameras you chose. Because you will have explicitly designed the test so that any differences will be equalised. It is not a problem with the cameras and lenses, it is a problem with the test.

The only thing we learned from that particular test is that the Pentax 28-45mm is quite good at f/14. That is hardly a surprise, all lenses are quite good between f/11 and f/16.