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Author Topic: H3 - Digital lens correction question  (Read 5927 times)

EricWHiss

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H3 - Digital lens correction question
« on: December 28, 2007, 08:54:08 pm »

While I'm happy with my Rollei 6008 and schneider and zeiss lenses,  I'm wondering about different upgrade paths for the future since eventually I'll want more than the 16mpix P20 (or at least a back that can do higher ISO well).    

I have been reading on the hasselblad site about the digital lens correction and wondered how much difference this makes in the images and what exactly is corrected.  

Will a decent lens with digital correction outperform a very good lens? And will something like that be worth changing platforms for?  Anyone out there know about this? Is this the future of digital capture?

Ideally, I'd love to see an image with and without corrections but I don't know if that's possible.

Thanks,
Eric
« Last Edit: December 28, 2007, 08:55:13 pm by EricWHiss »
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rethmeier

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H3 - Digital lens correction question
« Reply #1 on: December 28, 2007, 10:21:09 pm »

Eric,
Hasselblad has been smart to keep their H3 system closed in order to rectify the mediocre
performance of some of their lenses.
The 35HC is a dog with out correction.
The 28HC was designed to be used with correction,nothing wrong with that!

However it all depends what you shoot.
If straight lines are not an issue,don't worry to much about it.

Also,you already have some great Rollei lenses,so stick with it and upgrade to a Hy6.

I haven't received my Hy6 body yet to use with my eMotion 75LV,therefore I haven't been able to test my Schneiders  ( 40+55PCS+ 60 + 80/2+90 Apo and 2.8/180)

However I'm pretty sure that 40mm will give me straight lines,I'm not that worried about the others.

Cheers,
Willem.
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EricWHiss

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H3 - Digital lens correction question
« Reply #2 on: December 28, 2007, 10:56:33 pm »

Willem,
Thanks for your reply - a bit off the thread topic but how do you like the 60 and the 80 f/2?  
Thanks,
Eric
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marc gerritsen

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H3 - Digital lens correction question
« Reply #3 on: December 28, 2007, 11:23:12 pm »

Hi Eric

If you create 2 layers out of the attached photos and toggle between the two
you will see how well Hasselblad's software works. (photos are not pp'ed yet
so don't judge the color, highlight etc)

I have been shooting for nearly 1.5 year with it and am so happy mainly with the straightening feature of the soft ware. I use the 35mm a lot and before the distortion feature was available
it was really hard to straighten the lines as most of the retrofocal lenses create moustache barrel distortion.

The software works automatically with all Hasselblad lenses.

cheers
Marc
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EricWHiss

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H3 - Digital lens correction question
« Reply #4 on: December 29, 2007, 01:27:28 am »

Quote
Hi Eric

If you create 2 layers out of the attached photos and toggle between the two
you will see how well Hasselblad's software works. (photos are not pp'ed yet
so don't judge the color, highlight etc)

.
.
.
cheers
Marc
[a href=\"index.php?act=findpost&pid=163729\"][{POST_SNAPBACK}][/a]


Hi Marc,
Thanks very much for that example!  I could see the differences very easily just in Safari - actually once you know what you are looking for you can see it in the thumbnails!  Clearly thats a big help, and probably more so for wide lenses. Does it do anything other than correct for lens distortion? Chromatic aberration, vignetting or other flaws?
Regards,
Eric
« Last Edit: December 29, 2007, 01:28:18 am by EricWHiss »
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Dustbak

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H3 - Digital lens correction question
« Reply #5 on: December 29, 2007, 03:49:51 am »

There are 3 different versions of DAC.

CA, distortion and Vignetting. The first 2 you can only turn on & off, the vignetting can be adjusted from 0-100.

I find all 3 working very well. Especially CA is really no problem, I don't particularly care about vignetting most of the time. The problem I sometimes have with the 35 and distortion correction is that it indeed straightens lines etc but distorts faces of people. I find the 35 a great lens but it needs to be stopped down somewhat to get really good results.

The other thing is MUP, this really makes a difference. The mirror slap is horrible and that is while using the delay feature. I get the mirror out of the way if I can.
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ixpressraf

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H3 - Digital lens correction question
« Reply #6 on: December 29, 2007, 04:10:47 am »

Hello Willem, and again it is more hassi bashing then telling real stuff.
For years i used rollei 6008 with various schneider PQ and zeiss lenses and they were not bad, actually they were verry good but........ A few years back, i switched to H2 and a world opened to me. When doing a lot of pack shots that need to be set free from the back ground, having perfect straight lines is a fantastic starter for fast use of the pen-tool, In architecture, lines are straight and so on. Also no traces of CA in the corners. as for rollei, the lenses where very good but really no  competition for the hassie H lens system (that is probably why they now are marketing a D-line in lenses. It is always the same question: will your clients be able to see it or will only you be able to see it. There are on this forum a lot of people telling storries about 35mm digital being equal in quality as digital backs.... let them do so: this means less competition for us and maybe it is even better so not to convince them....
At the end it always boiles down to one simple fact: do you make the money to invest in a new digital system with new hassie or rollei lenses or do one only make enough to justify a canon 1dsII or something like that. Few will admit that they do not make that kind of money and keep on finding excuses for themselves.....
As for the corrections in flexcolor: they are as explained by Dustback simply perfect. Just working in the background ensuring best optical performance of your lenses.
You can also find a lot of explanation in  Victor or on the hasselblad website.
Just go for it.
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rethmeier

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H3 - Digital lens correction question
« Reply #7 on: December 29, 2007, 07:27:36 pm »

Dear ixpressraf,
I certainly didn't want to look that I was bashing the H system.
Their latest H3D system is certainly the most advanced out there.
I was only pointing out that with their system they can make an o.k lens great!
Their 35HC before DAC was unusable for architecture.

As I don't have my Hy6 body yet,I can't test my current Rollei lens range with my eMotion-75LV.

Also there is nothing stopping Sinar to also have DAC in their new eXposure software.
Hasselblad is in the lead in that department.

Happy New Year!

Willem.
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EricWHiss

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H3 - Digital lens correction question
« Reply #8 on: December 29, 2007, 09:05:24 pm »

Yes, I was thinking too that really any of the back manufacturers could add this kind of correction to their software - probably Phase will do the same thing if they offer a total solution with Mamiya since they have already partnered.  

I guess these kinds of corrections help all lenses but will not make a lens sharper wide open for example or affect bokeh or other non quantifiable qualities of the optics.   Maybe someday?
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rethmeier

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H3 - Digital lens correction question
« Reply #9 on: December 29, 2007, 11:04:22 pm »

Actually,
if you have some time on your hands,you could calibrate all your lenses with Pano-Tools
for distortion and CA, and apply each correction to each lens.

That exactly what Hasselblad would have done.

Please correct me if I'm wrong.

Cheers,

Willem.
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marc gerritsen

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H3 - Digital lens correction question
« Reply #10 on: December 29, 2007, 11:18:49 pm »

Hi Willem
I considered doing that before flexcolor and tried out the software.
The only thing is that you have to really know what you are doing
short of being a software expert, but not impossible.
I certainly seem to have a hard time calibrating screens, color management,
lens distortions, etc.
cheers
Marc
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Dinarius

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H3 - Digital lens correction question
« Reply #11 on: December 30, 2007, 08:57:19 am »

A huge amount of what I do it fine art copy work for catalogue.

So, I will need to decide which lens to use on a day to day basis for this work.

I would dearly love a macro, with a flawless flat field, that is slightly longer than normal. 85mm would be ideal. But, it doesn't exist and the 120mm is too long.

So, could someone who uses the 80mm regularly and who has used it for copy work tell me if it is up to the job? Does it also need correction in the software?

Many thanks.

D.
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Dustbak

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H3 - Digital lens correction question
« Reply #12 on: December 30, 2007, 09:07:46 am »

I use the 80 a lot for table top work and catalogue work. I have been traumatized by the Mamiya 80 (645) so I am a bit anxious of using an 80 however the HC80 is very sharp, distortion is virtually not there. All corrections will be dealt with by flexcolor (you have to process to either tiff or JPG in that case, no DNG) but there is not a lot of corrections. With the 35 I can see the difference clearly with the 80 I don't.

I also do a lot of converting to DNG first because some things need to be handled by PS actions. No problem with the 80.

Nope, I find the 80 actually a very good lens, sofar it is the lens I use most. You might consider getting one of the extension rings as well to be able to focus closer.
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EricWHiss

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H3 - Digital lens correction question
« Reply #13 on: December 30, 2007, 02:28:06 pm »

Quote
A huge amount of what I do it fine art copy work for catalogue.

So, I will need to decide which lens to use on a day to day basis for this work.

I would dearly love a macro, with a flawless flat field, that is slightly longer than normal. 85mm would be ideal. But, it doesn't exist and the 120mm is too long.

So, could someone who uses the 80mm regularly and who has used it for copy work tell me if it is up to the job? Does it also need correction in the software?

Many thanks.

D.
[a href=\"index.php?act=findpost&pid=164019\"][{POST_SNAPBACK}][/a]

You are probably not talking about the Rollei 80mm but they do make a 80mm f/2.8 PQS planar that might do the job well.   I've used this lens extensively and it has astounded me in its performance.  I did a series of images with small items on a table top and it appears it would be excellent for copy work, but the Rollei 90mm APO Macro is probably better still.  Incredibly sharp.   I tend to use rodagon APO enlarger lenses for copy work mostly, though.
« Last Edit: December 31, 2007, 02:13:54 am by EricWHiss »
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Gary Ferguson

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H3 - Digital lens correction question
« Reply #14 on: December 31, 2007, 06:25:29 am »

Quote
While I'm happy with my Rollei 6008 and schneider and zeiss lenses,  I'm wondering about different upgrade paths for the future since eventually I'll want more than the 16mpix P20 (or at least a back that can do higher ISO well).   

I have been reading on the hasselblad site about the digital lens correction and wondered how much difference this makes in the images and what exactly is corrected.   

Will a decent lens with digital correction outperform a very good lens? And will something like that be worth changing platforms for?  Anyone out there know about this? Is this the future of digital capture?

Ideally, I'd love to see an image with and without corrections but I don't know if that's possible.

Thanks,
Eric
[a href=\"index.php?act=findpost&pid=163701\"][{POST_SNAPBACK}][/a]

Eric, I suspect it will be an increasingly big deal over time. Freeing the lens designer from having to keep straight lines reasonably straight will allow them to make astonishing gains in resolution.  Two pieces of anecdotal evidence.

I've never been lucky enough to use the Hasselblad H series 28mm, but the MTF chart is truly amazing. It's a gold standard optic, but it needs software correction.

Secondly, I've used Hasselblad V series lenses for thirty years, and a good part of that time was spent struggling with their indifferent 40mm lenses. However the latest 40mm IF lens was a revelation in terms of resolution, but you pay a serious price in distortion. Apart from the 30mm fisheye the 40mm IF is the worst distorting lens in the V series line-up.

I take from those two examples that lens designers can work retro-focus, wide-angle miracles. But only if they're freed from the constraint of correcting distortion optically and can leave this to the software.
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rsmphoto

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H3 - Digital lens correction question
« Reply #15 on: December 31, 2007, 12:26:56 pm »

Yes and no. My favorite lens is the 50-110 zoom and I use it quite a bit (along with the 35 and 28), and am truly impressed with how DAC works with this lens. Not sure I'd want to start mapping this lens with Pano-Tools.

Best in the New Year to you all,

Richard

Quote
Actually,
if you have some time on your hands,you could calibrate all your lenses with Pano-Tools
for distortion and CA, and apply each correction to each lens.

That exactly what Hasselblad would have done.

Please correct me if I'm wrong.

Cheers,

Willem.
[a href=\"index.php?act=findpost&pid=163975\"][{POST_SNAPBACK}][/a]
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EricWHiss

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H3 - Digital lens correction question
« Reply #16 on: December 31, 2007, 02:01:17 pm »

Quote
Eric, I suspect it will be an increasingly big deal over time. Freeing the lens designer from having to keep straight lines reasonably straight will allow them to make astonishing gains in resolution. 
.
.
.
[a href=\"index.php?act=findpost&pid=164182\"][{POST_SNAPBACK}][/a]


I guess this is just the beginning then. I was originally wondering if there was a way to extract more detail too besides the distortion correction but hadn't though that far ahead (designing the lens with software correction from the start).
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rethmeier

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H3 - Digital lens correction question
« Reply #17 on: December 31, 2007, 04:34:21 pm »

If the lens has slight barrel or pin cushion,than it's not such a problem.
Easy to fix in post.
Barrel and pin combined with moustache that's where the problems start.
Cheers,
Willem.
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vjbelle

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H3 - Digital lens correction question
« Reply #18 on: January 01, 2008, 04:47:00 pm »

Quote
I find the 80 actually a very good lens, sofar it is the lens I use most. You might consider getting one of the extension rings as well to be able to focus closer.
[a href=\"index.php?act=findpost&pid=164021\"][{POST_SNAPBACK}][/a]

You are dead on the money!! The HC80 is extremely sharp and is also one of the lenses I use the most.  The 150 and 210 are in a world of their own.  I tested them both against the stellar V series 180 and the difference can easily be seen.  I don't use any of the wide angle H lenses - I prefer to use an Alpa with Digitar lenses for those situations.

Victor
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