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Author Topic: Hy6 prismfinder designet to fit sensor size?  (Read 20540 times)
godtfred
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« Reply #60 on: March 11, 2007, 05:47:41 PM »
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The 28 is a 28 ,however there still is the crop factor of the sensor.
In real terms the lens is a 30.8 mm lens,which is still pretty good!
[a href=\"index.php?act=findpost&pid=106102\"][{POST_SNAPBACK}][/a]
The Hasselblad catalogue/brochure states this for the 28mm lens:

"the HCD 4/28 mm lens is designed solely for digital use. this means that the lens is
designed for a format of 37x49 mm and does not cover the film format (41.5x56mm)."

Does this not mean that there is no crop factor involved, and that the 95 degree diagonal angle of view does not apply? (Making it approx. the same as a 20mm on a FF canon with a 94 degree diagonal angle of view...)

I was under the impression that this lens is in fact a true 28 on the H3D, can anyone confirm this?

-axel
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Axel Bauer
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« Reply #61 on: March 11, 2007, 05:57:35 PM »
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Jo ,you're wrong!
The H3 22 and 39 sensors are not full frame,we all know that!
Like I said before,a 30.8mm lens is still very wide! 
[a href=\"index.php?act=findpost&pid=106108\"][{POST_SNAPBACK}][/a]

Here we go again!    

I'm right, quoting from the link above...

'The HCD 4/28 mm lens is designed solely for digital use. This means that the lens is
designed for a format of 37x49 mm and does not cover the film format (41.5x56mm).'

Believe me now?

Jo S.x
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rethmeier
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« Reply #62 on: March 11, 2007, 06:55:38 PM »
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O.K!
So the 35,50,80,150,210 etc are 35,50,80,150,210 ?

Anyway the 28 is a 28.9 mm.

http://www.hasselblad.com/media/61395063-a...f8-HCD28_UK.pdf

And the angle of view varies on which sensor is being used.
It certainly won't be the same with the new Hasselblad 31MB sensor.

Cheers,
Willem.

And please correct me if I'm wrong!!!!!!!!!!!!!!!
« Last Edit: March 11, 2007, 07:10:28 PM by rethmeier » Logged

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« Reply #63 on: March 11, 2007, 07:37:08 PM »
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The 28mm is a 28mm (well.. around about 28mm). So on a H3D-39 it will appear to be approximately a 30mm - even if the image circle only covers the smaller area. The 28mm describes the actual physical measurement of the lens irrelevant of the sensor size.

A 28mm for 35mm format is still a 28mm even if it cant cover anything larger format.

Svein Erik
« Last Edit: March 11, 2007, 07:38:18 PM by sundstei » Logged
rethmeier
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« Reply #64 on: March 11, 2007, 08:00:33 PM »
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The 28mm is a 28mm (well.. around about 28mm). So on a H3D-39 it will appear to be approximately a 30mm - even if the image circle only covers the smaller area. The 28mm describes the actual physical measurement of the lens irrelevant of the sensor size.

A 28mm for 35mm format is still a 28mm even if it cant cover anything larger format.

Svein Erik
[a href=\"index.php?act=findpost&pid=106140\"][{POST_SNAPBACK}][/a]

Thanks Svein!
I knew I was right a along!
Cheers,
Willem.
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Willem Rethmeier
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godtfred
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« Reply #65 on: March 12, 2007, 02:38:40 AM »
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The 28mm is a 28mm (well.. around about 28mm). So on a H3D-39 it will appear to be approximately a 30mm - even if the image circle only covers the smaller area. The 28mm describes the actual physical measurement of the lens irrelevant of the sensor size.

A 28mm for 35mm format is still a 28mm even if it cant cover anything larger format.
[a href=\"index.php?act=findpost&pid=106140\"][{POST_SNAPBACK}][/a]
I'm getting very confused by this...

The HC lenses cover the 41,5x56mm filmformat giving a 1.1 crop factor in the image circle when you use either the kodak 22 or 39 mpix chips.

The HCD lenses though (currently the 28mm) cover only the 37x49 format, thus NOT cropping anything in the imagecircle. Are you guys telling me that it still has a 1.1 crop factor, even though it does NOT crop the imagecircle. That would be the same as saying a FF canon crops all the canon lenses with a slightly larger image circle (like all the TS/E lenses, making the 28mm TS/E something like a 40/50 mm?)

The only factor I can tell that would allow one to claim a crop factor involved would be the larger sized mirror box on the H-system bodies, and the subsequent lengt from lens exit pupil to sensor created by this oversized (in the HCD lens case) mirror box...

-axel
(not flaming, just very curious, and starting to think Hasselblad is in deep waters with this full frame 48mm system stuff on the HCD lenses if it in fact still is a crop factor involved on the HCD lenses...)
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Axel Bauer
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« Reply #66 on: March 12, 2007, 02:55:23 AM »
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maybe i missunderstand you but i dont see the problem...( anyway axel is right )
a 28mm lens is a 28mm lens on whatever sensor or film size you mount it. same lens still will be a 28mm on 4x5" ( which it will not cover ofcourse ) and it will still be a 28mm on a 35mm sensor.
its the sensor size alone which determins the crop factor, and this 1.1 or 1.3 maths only says that a 28mm on a 36x49 sensor shows the same image field than a lens with 31mm would show on a "full" 645 sensor/film, cause here the image field is larger and therefor the lens need to be longer for the same image.
« Last Edit: March 12, 2007, 02:56:48 AM by rehnniar » Logged

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« Reply #67 on: March 12, 2007, 03:11:53 AM »
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Dear Axel,

the 28mm is a 28mm and remains a 28mm as long as it exists, no matter which camera, which film size or which sensor size it is used with/on.

The important here is the lens angle, which gives the size of the image circle. This produced image circle will (or will not) cover a certain size or a certain sensor size. The size of the film/sensor is important here. And since we are speaking digital, the current size of the Kodak sensors are 36.7x49mm. And this is NOT the same size as the 4.5x6 flim size (41.5x56mm).

Important is the effect of the lens and compare what can be compared: this particular 28mm will have a certain crop (framing) which corresponds to the same crop with a 31mm (according to Willems calculation) on a (film) 4.5x6.0 (exactly 41.5x 56mm).

Hope this helps to understand, that whatever one says "full frame" is a relative wording.

Best regards,
Thierry

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I'm getting very confused by this...

The HC lenses cover the 41,5x56mm filmformat giving a 1.1 crop factor in the image circle when you use either the kodak 22 or 39 mpix chips.

The HCD lenses though (currently the 28mm) cover only the 37x49 format, thus NOT cropping anything in the imagecircle. Are you guys telling me that it still has a 1.1 crop factor, even though it does NOT crop the imagecircle. That would be the same as saying a FF canon crops all the canon lenses with a slightly larger image circle (like all the TS/E lenses, making the 28mm TS/E something like a 40/50 mm?)

The only factor I can tell that would allow one to claim a crop factor involved would be the larger sized mirror box on the H-system bodies, and the subsequent lengt from lens exit pupil to sensor created by this oversized (in the HCD lens case) mirror box...

-axel
(not flaming, just very curious, and starting to think Hasselblad is in deep waters with this full frame 48mm system stuff on the HCD lenses if it in fact still is a crop factor involved on the HCD lenses...)
[a href=\"index.php?act=findpost&pid=106183\"][{POST_SNAPBACK}][/a]
« Last Edit: March 12, 2007, 03:14:45 AM by thsinar » Logged

Thierry Hagenauer
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godtfred
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« Reply #68 on: March 12, 2007, 04:06:41 AM »
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the 28mm is a 28mm and remains a 28mm as long as it exists, no matter which camera, which film size or which sensor size it is used with/on.

The important here is the lens angle, which gives the size of the image circle. This produced image circle will (or will not) cover a certain size or a certain sensor size. The size of the film/sensor is important here. And since we are speaking digital, the current size of the Kodak sensors are 36.7x49mm. And this is NOT the same size as the 4.5x6 flim size (41.5x56mm).

Important is the effect of the lens and compare what can be compared: this particular 28mm will have a certain crop (framing) which corresponds to the same crop with a 31mm (according to Willems calculation) on a (film) 4.5x6.0 (exactly 41.5x 56mm).
[a href=\"index.php?act=findpost&pid=106187\"][{POST_SNAPBACK}][/a]
Thanks Thierry, that's what I was looking for...

The bit about a lens being a certain mm. no matter for what format, I have understood after my first foray into medium and large format many years ago.

It seems where I got confused by HB "marketing speak" is where one starts to compare a 28mm for the 36.7x49 format (22/39mpix chip) with a 35mm for the 41.5x56 format. This is like comparing 35 with 645 and a different format altogether.

If one disregards the image circle bit for the 28, it needs a conversion factor of 1.1 to be compared to all other HC lenses, and to be treated as a 30,8mm when being compared to both 645 and 35mm for easy understading of this lens in relation to other formats.

What is clear to me though, is that this lens provides a 95 degree diagonal viewing angle "on chip" for the 22/39 mpix kodak chips, making it almost directly comparable to a 20mm on a FF canon (94 degree diagonal viewing angle, so maybe more like a 19,5mm on the canon...) if one needs to easily grasp what this lens offers in terms of wide angle. (If this is not true, and HB gives the viewing angle for a 41.5x56 format in its documentation about this lens, then someone at their marketing department need to be fired as it is seriously misleading!)

Anyways, thanks for the clarification, the 28mm does indeed have a 1.1 conversion factor when being compared to other formats using 41.5x56 film/sensor size as the base for the comparison.

-axel
(after re-reading this post, I find that my terminology is'nt at its greatest here, but I hope I have understood, and that what I just wrote is understandable    )
« Last Edit: March 12, 2007, 04:08:56 AM by godtfred » Logged

Axel Bauer
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« Reply #69 on: March 12, 2007, 06:15:38 PM »
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Thats not quite right.

The HCD28mm lens is designed for the 22 / 39 MP sensor so 28mm is actually a 28mm lens.  Important if you need really wide angle lenses and don't want to suffer from crippling lens conversion factors...

Which some might argue are present on the RZ.   

Also a little known fact is that he metering system in the new finder is more accurate and also faster to meter.

Jo S.x
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why do use quotes if what you are saying has absolutely nothing to do with what you are quoting?
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« Reply #70 on: March 12, 2007, 06:23:46 PM »
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Thanks Svein!
I knew I was right a along!
Cheers,
Willem.
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just read this whole exchange....another amazing example of hass marketing talk....so much that you can quote directly from the website/manual and still get it wrong....so really after announcing a 28 FF with big fanfare it turns out to be a 31 FF and still does not cover the whole area for film....
i just don't get what the point of trying to mislead consumers with a product that is so specialized anyway....nobody is not NOT going to buy the lens because it is a 31 (i hope)....
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josayeruk
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« Reply #71 on: March 13, 2007, 02:54:31 AM »
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Okey Dokey!

So the 28mm remains a 28mm regardless of what it goes on, sure sure I get that.

But I believe what differentiates the HC lenses (50, 120 etc etc) to the H2D 28.9(  ) is that the angle of view is not affected when it is placed on an H3D.

Whereas the other HC lenses will be affected by a crop factor... or whatever else you want to call it.

Either way its a very nice lens when I borrowed it for a couple of days.

Jo S.x
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Willow Photography
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« Reply #72 on: March 13, 2007, 03:55:00 AM »
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just read this whole exchange....another amazing example of hass marketing talk....so much that you can quote directly from the website/manual and still get it wrong....so really after announcing a 28 FF with big fanfare it turns out to be a 31 FF and still does not cover the whole area for film....
i just don't get what the point of trying to mislead consumers with a product that is so specialized anyway....nobody is not NOT going to buy the lens because it is a 31 (i hope)....
[a href=\"index.php?act=findpost&pid=106345\"][{POST_SNAPBACK}][/a]


Based upon all your writings about Hasselblad it sounds to me like you hate Hasselblad and loves to write negative about every thing Hasselblad does.

Now it is not only the H2 you hate, but also the lenses.

It has become so predictebal that it is not worth reading anymore.

Every brand has qualities and faults.

Hasselblad would not be where it is today by being what you claim it is - only bad.

Try to get some grey shades into your opinions about a brand.

Then your opinion will be more interesting and credible.


Willow
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« Reply #73 on: March 13, 2007, 08:15:59 AM »
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I have a PhD in maths, and I'm confused.

Some of my cameras take 35mm film.
Some take MF film.
Some have digital sensors, the size of film.
Some have sensors cropped to various sizes.

I have a variety of lenses.
And all have lenses defined by millimeter numbers Mi.

These millimeter numbers Mi describe the distance of the nodal point of the lens to the film plane when the lens is focused at infinity.
These millimeter numbers Mi are supposed to magically relate to the angle of view of the lens, because after all we have different lenses for different angles of view.

And yet when I stick an 80mm lens on a Hasselblad film camera (nice camera!)it's a "normal " lens . On a 35mm camera it's a short-tele portrait lens.

Maybe just giving millimeter figures is not descriptive of field of view without defining the image size.

Which is why the marketing guys love it. You sell somebody a "medium format" camera except it's cropped and  the field of view of the lens is reduced, but you tell him he's got the whole thing.
 
I'd feel more comfortable if people told me what field of view the lens had on their camera system, at a given aspect ratio.

As usual, people will tell me this is total nonsense. For those who like the less travelled road, but prefer it paved, here is a link to an FOV calculator.

http://www.mat.uc.pt/~rps/photos/angles.html

Edmund
« Last Edit: March 13, 2007, 08:16:35 AM by eronald » Logged

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« Reply #74 on: March 13, 2007, 08:45:57 AM »
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giving millimeter figures is not descriptive of field of view without defining the image size.

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Correct

No PHD required

The perspective and DOF characteristics are however defined by the focal lenghth

SMM
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« Reply #75 on: March 13, 2007, 08:53:52 AM »
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May I correct Sam, with all my due respect:

- the perspective does not depend on the focal lenght but solely on the view point (distance & angle to the subject).

- The dof depends on the aperture & the reproduction size, and does also not depend on the focal length.

Thierry

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Correct

No PHD required

The perspective and DOF characteristics are however defined by the focal lenghth

SMM
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« Reply #76 on: March 13, 2007, 09:09:00 AM »
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May I correct Sam, with all my due respect:

- the perspective does not depend on the focal lenght but solely on the view point (distance & angle to the subject).

- The dof depends on the aperture & the reproduction size, and does also not depend on the focal length.

Thierry
[a href=\"index.php?act=findpost&pid=106410\"][{POST_SNAPBACK}][/a]

The perspective and DOF characteristics are however defined by the focal lenghth.. given a fixed field of view and shooting point

ie a 65mm on 54 a f8 looks different from an 16mm on an APS chip at f8 even though the field of view is the same - the DOF is different

An 80mm f4 4 on a blad croped in half looks the same as an 80f4 on a dslr the perspective is the same but the field of view less

Bottom line - bigger chip = less DOF for a given view at a given aperture

world record for off topicness??

SMM
« Last Edit: March 13, 2007, 09:09:57 AM by Morgan_Moore » Logged

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« Reply #77 on: March 13, 2007, 09:13:21 AM »
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Based upon all your writings about Hasselblad it sounds to me like you hate Hasselblad and loves to write negative about every thing Hasselblad does.

Now it is not only the H2 you hate, but also the lenses.

It has become so predictebal that it is not worth reading anymore.

Every brand has qualities and faults.

Hasselblad would not be where it is today by being what you claim it is - only bad.

Try to get some grey shades into your opinions about a brand.

Then your opinion will be more interesting and credible.
Willow
[a href=\"index.php?act=findpost&pid=106374\"][{POST_SNAPBACK}][/a]

did you even read what i wrote? i said nothing negative abut hass lenses....
someone pointed out that what hass claims is wrong, of course the ususal people jumped on him , even quoting has literature and it turns he is right! i don't get deceptive advertising for a product like this.....and like i said....anyone would be stupid NOT to buy the 28 becaue it is still the widest lens out there.....
anyne working with digital knows about lensfactors...whenever anyone asks me: what is that lens on this camera...i always say it is the same lens...you might just get less of it....to me a 180 for the P30 is still a 180....just cropped....the lenses haven't changed, just what we get from them and with different sensor sizes it gets even more complicated....either way i know what a 28 will give me.....
but when a company takes that and by marketing speak (some of it quoted here earlier) makes it seem like you are getting more then you think you are (which some people here obviously did and by reading the material i was very confused as well) i just don't think that is right.....do you think that this is the way to advertise this lens?
of course the 80mm is the 80 and there is no other claim about it....the 28 on the mamiya will cover the whole area, but it won't be any wider on a P45/ C39 then the Hass 28...so what is the point....
and actually, because you mentioned it....i don't like hass lenses.....the 80mm is fine, i have no problems with it...it is fine, not great (which for the money it should be) and the zoom is fine optically, only very slightly better then my 10 year old mamiya zoom which weighs a fraction and cost even less....i was never very happy about my hass V lenses either (40, 80, 120)...fine, but nothing to write home about...the only good one was the 38 on the hass wide body....nice lens....these are all my personal experiences and i am sharing them just like you do....
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« Reply #78 on: March 13, 2007, 09:26:14 AM »
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Sam

if you want to compare the dof you have to compare what can be compared: of course a smaller format on APS has more dof than on the 4x5" film. But you cannot compare like this: you have to compare at the same reproduction scale, thus enlarge the APS to the same size as the 4x5 and then you will see what I mean.

As for perspective, it is the same: make 2 shots from exactly the same view point AND with a different focal lens, the first shot with i.e. a 47mm on 4x5 and the second shot i.e. with a 600mm on 4x5. Process and look at it: the 47 will give you a smaller reproduction scale. to compare you have to enlarge it to the same size as the 600mm shot and then you will see the same depth of field (and the same perspective = converging lines are the same).

That is what I mean.

Thierry

Quote
The perspective and DOF characteristics are however defined by the focal lenghth.. given a fixed field of view and shooting point

ie a 65mm on 54 a f8 looks different from an 16mm on an APS chip at f8 even though the field of view is the same - the DOF is different

An 80mm f4 4 on a blad croped in half looks the same as an 80f4 on a dslr the perspective is the same but the field of view less

Bottom line - bigger chip = less DOF for a given view at a given aperture

world record for off topicness??

SMM
[a href=\"index.php?act=findpost&pid=106415\"][{POST_SNAPBACK}][/a]
« Last Edit: March 13, 2007, 09:35:17 AM by thsinar » Logged

Thierry Hagenauer
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« Reply #79 on: March 13, 2007, 09:43:00 AM »
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Hasselblad would not be where it is today by being what you claim it is - only bad.

It is dangerous to show popularity as a proof of quality. Think Ford, McDonalds, Bose, etc - all manage to sell well despite producing some of the lowest quality products in their respective industries.
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