Thanks again for all the comments. I have the 150mm f2.8 prime so I'll take that outside and see how it performs at around f4.5-8. I don't have an equivalent focal length for the 'Blad so I shan't carry out a comparison. Based on several of your comments, I'm cautiously optimistic that the results will be an improvement. If so, I'll sell the 45-85 and 80-160 and buy a couple of s/h primes.
I'll keep you posted; thanks again for all your observations.

Interesting comments everyone - thanks for the input.

As someone who's used Pentax gear since the late 1960s, I have always had great respect for it glassware, whether for 6x7 or 35mm. A few weeks ago I bought a lovely 645D with 3 lenses and couldn't wait to get out there and start snapping. I already use the Contax 645 system, Mamiya RZ67 gear and have a Hasselblad H1 - these all take an Ixpress 22Mp back (88Mp with multi-shot) and have consistently produced stunning results. However, carrying the Image-Bank around (it holds the battery and a hard drive for the images) can be awkward so I thought lets go for the Pentax, with its self-contained digital back and 40Mp sensor.

I absolutely love the camera - it's not up for debate, it's a gem and I was already scoping the 645Z before I downloaded some images from the 645D. I was not impressed but I was shooting with all 3 lenses wide-open which is how I always test my glass as it will usually expose any significant flaws. I then decided to take out the H1 with the 50-110 alongside the 645D and 45-85 - both lenses have nearly equivalent focal lengths. I shot a variety of images and once again, I found the Pentax glass producing huge chroma problems - purple fringeing around all highlights; the Hasselblad's Fuji-made lenses had none of the problems. I'm exasperated.

I've attached a couple of small crops from the same view shot by both systems - the Pentax's issue of chroma is all too obvious. I'm sure that low contrast subjects shot in a studio will prove to be fine but so far I'm thinking about ditching the 645D (such a shame) and just keeping my trusty old Pentax 6x7s and film.

Thank you everyone for your kind welcome!

I have been enjoying mixed fortunes with my Pentax 645D...love the camera but to date the 3 lenses have been a disappointment. I plan to try them at smaller apertures - wide open I have been having big issues with chroma and softness. I plan to shoot with the lenses at f8 and will pitch them against the 'Blad and Contax 645 glassware when fully open. To date the Fujinon (Hasselblad H) and Zeiss (C645) have been much sharper - but sharpness is not the only quality. I have to say though that the 645D body inspires more confidence than the 'Blad and its weatherproofing, though not its handling, aces the Contax.

More anon in the appropriate forum.

Best wishes to all,
Graham

Hi Martin, sounds like a typical Welsh mid-summer...what's the problem? You're right about fully waterproof - I have that (well, 'weatherproof') in my Fuji X-T1 and its top zoom lenses. I'll have to save up quite a few pennies to afford the Pentax weatherproof lenses for the 645D.

Thanks for the welcome guys.

By the way Stuey, I used to live near your part of the Principality; I had a cottage in Carneddi, just atop Bethesda. I had such fun on my Honda CBX750 back in the 80s, N Wales is great biking country as well as a photographer's paradise.

I'm hoping to get out and about tomorrow with the 645D and then repeat the same views with the Hasselblad. Can't wait...

My involvement with Pentax gear goes back to the late 1960s with a SV and a Super Takumar 50 1.4. The absence of a meter (I couldn't afford the pentaprism accessory meter back then) made you calculate light readings by eye which has served me well ever since. For 35mm work in the 70s through to the late 90s, I moved away to Contax and Zeiss but kept my faith with Pentax in the form of the trusty old 6x7 - I am forever indebted to the Pentax legend, Sam Haskins, for introducing me to the '35mm SLR on steroids' at his studio in Kensington back in 1971.

I have re-acquired a SV, this time with the accessory meter, but have just bought a 645D with the 150mm f2.8, 45-85 and 80-160 zooms and so hope to contribute to this forum as I learn to use the gear. I've been using a Hasselblad H1, Contax 645 and Mamiya RZ67 with an Ixpress 132C digi-back - great results! However, I'm really looking forward to pitting the 645D and its glass against the 'Blad and its lenses. It's not a pixel battle - just a matter of image quality; and of course the greater portability of the Pentax as the back is self-contained.

Just waiting for the weather here in S Wales to improve - I know the camera is shower-proof but the lenses aren't...

More anon....