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Thread: Hassy HCD lens image circle

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    Hassy HCD lens image circle

    Anyone with knowledge about how big the image circle for the HCD series lens? I am in the process of getting the shift lens adaptor for Alpa 12FPS and now wondering which one to get (Contax645 or the Hasselblad H)

    Would be nice to have some information regarding this.
    I am using a 44x33 CMOS sensor as back, so would just want to know how much I can shift... will it be the full 12mm available to the adaptor?

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    Re: Hassy HCD lens image circle

    From the Hasselblad MTFs, about 63mm.

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    Re: Hassy HCD lens image circle

    Quote Originally Posted by kimyeesan View Post
    Anyone with knowledge about how big the image circle for the HCD series lens? I am in the process of getting the shift lens adaptor for Alpa 12FPS and now wondering which one to get (Contax645 or the Hasselblad H)

    Would be nice to have some information regarding this.
    I am using a 44x33 CMOS sensor as back, so would just want to know how much I can shift... will it be the full 12mm available to the adaptor?
    The Contax lenses have been designed as to cover the full 56x42mm image area and even have image circle comparable to those of 6x6 lenses, the Hasselblad HCD have been designed for cropped sensors and thus have reduced image circle... I suggest you go for the Contax.....

    I am now working on a project where I'm converting a Rollei X-Act2 as to work with Contax lenses and accept Contax MFDBs on it (the camera will have focal plane shutter)... If Contax lenses are focused to their minimum focusing distance and are stopped down a bit, they can work well on a view camera even with sensors larger than yours....

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    Re: Hassy HCD lens image circle

    The Hasselblad HC lenses are designed to cover 645 format, there are only three HCD lenses, 24,28 mm for which
    there is no equivalent in the Contax system anyway as far as i can tell, and then there exists the HCD 35-90 zoom.
    The HCD lenses are designed to cover 49x36 mm sensors so the required image circle is 61mm and as mentioned here
    above its actually 63mm. For a 44x33mm sensor the required image circle is 55mm so 12mm shift won't work IMO.

    Regards,
    Ralf
    Last edited by rmueller; 12th December 2015 at 03:21. Reason: just now realized it was specifically asked for HCD lenses and not HC lenses in general

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    Re: Hassy HCD lens image circle

    Quote Originally Posted by rmueller View Post
    The Hasselblad HC lenses are designed to cover 645 format, there are only three HCD lenses, 24,28 mm for which
    there is no equivalent in the Contax system anyway as far as i can tell, and then there exists the HCD 35-90 zoom.
    The HCD lenses are designed to cover 49x36 mm sensors so the required image circle is 61mm and as mentioned here
    above its actually 63mm. For a 44x33mm sensor the required image circle is 55mm so 12mm shift won't work IMO.

    Regards,
    Ralf
    This is all correct, the Hasselblad H lenses are all of shorter diameter image circle than their respective C645 lenses though, not only the HCD ones. I considered the HTS too as to use the my Contax lenses on it, but I decided to go for a view camera instead which would allow many additional movements and would "extract" even more image circle if the lenses are to be used with their focusing set to minimum or near that. The luck of wider than 35mm lens on the Contax, can be solved if one converts the Samyang 24mm f3.5 T-S lens which has 74mm image circle, (another project I'm working on currently) as to fit on the Contax... It is a rather simple modification which requites the shift mechanism of the lens (which is bolted on) to be removed by simply unscrewing it off and then use a shorter by 19mm spacer which will have a Contax mount at the end.... (the rear element of the lens is recessed enough to allow this).
    Last edited by T.Dascalos; 12th December 2015 at 04:59. Reason: grammar

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    Re: Hassy HCD lens image circle

    Quote Originally Posted by rmueller View Post
    The Hasselblad HC lenses are designed to cover 645 format, there are only three HCD lenses, 24,28 mm for which
    there is no equivalent in the Contax system anyway as far as i can tell, and then there exists the HCD 35-90 zoom.
    The HCD lenses are designed to cover 49x36 mm sensors so the required image circle is 61mm and as mentioned here
    above its actually 63mm. For a 44x33mm sensor the required image circle is 55mm so 12mm shift won't work IMO.

    Regards,
    Ralf
    The image circle is 63mm, does it mean optimal IC or absolute IC. Optimal IC means that outside of this 63mm is all light fall off and or image quality deteriorating. Absolute means just complete blackness.

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    Re: Hassy HCD lens image circle

    Quote Originally Posted by kimyeesan View Post
    The image circle is 63mm, does it mean optimal IC or absolute IC. Optimal IC means that outside of this 63mm is all light fall off and or image quality deteriorating. Absolute means just complete blackness.
    There are no official figures or measurements of the image circle, but I can say that it is smaller on the 24mm than on the 28mm and varies with focal length on the zoom.
    Last edited by jerome_m; 13th December 2015 at 03:59. Reason: deleted "no dark corners on film"

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    Re: Hassy HCD lens image circle

    When I use the 28 mm with a film back, the negatives show dark corners.
    Frans Rutten
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    Re: Hassy HCD lens image circle

    Quote Originally Posted by Miller View Post
    When I use the 28 mm with a film back, the negatives show dark corners.
    Good to know, thank you. I was told otherwise, but it was second-hand info and I'll edit my post accordingly.

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    Re: Hassy HCD lens image circle

    All zoom lenses expand their projected image circle as they are zoomed to their telephoto end... OTOH, all lenses expand their image circle the nearest they are focused. As a result, there are MF lenses that their use with movements is limited on an ALPA, but the same lens can be used on a view camera if the lens is focused at (or near) its nearest focusing distance and then the lens is re-focused to infinity by adjusting appropriately the distance from the sensor (using the view camera's focusing knob)... Usually, for one to achieve the optimum performance out of an MF lens which is used on a view camera, he needs to double focus the lens using both the focusing ring and then the camera's focusing knob as to find the shortest image circle that allows compatibility with the movements required.... Unfortunately, technical cameras (like the Alpa) don't offer on body focusing and thus one can't expand the image circle of the lens, which is the main reason why I much prefer using a small view camera instead...

    OTOH, for the cost required as for one to have interface communication between lens mount and MFDB, one can buy a small view camera and use a S/H MF body which he will then have to take apart and use the mount on the front standard and then the back plate of the MF camera body on the rear standard and additionally, to make an exterior control box (or use what is left from the camera body) on which he will house the electronics.... Of course this needs skills and having access to the camera's service manual as to spot all connections, but the reward can be fantastic as one will end up having a view camera which will be fully compatible with his MF system as an additional body....

    The solution I ended up to do the above, is to chose the Rollei X-Act as my view camera (because the body - other than being small - has been designed as to be used with MF lenses and MFDB and can allow for one to use a mirrorless on the rear standard) and then use a S/H Contax 645 body from which I will remove the mount and CPU contacts and integrate them on the removable disc of the front standard... Then I'll have the back plate of the camera body removed (with the CPU contacts, the focal plane shutter and the hinges for the MFDB) and integrate them on the removable disc of the rear standard. Then, I'll retain the rest of the body, attach it to the back of the x-act2's rail and have extension cables from the remains of the body that will connect back the CPU interface (via multi-pin plugs) to the front and rear standard.... For optical VF, I'll be converting a film back that will have a screen where the film plane should be and use a the Hartblei chimney finder for loop as to be able to just attach the film back instead of the MFDB, or use the MFDB's LV...

    That way, I'll be able to remove the Contax parts from the rear or the front standards whenever I want and be able to use a mirrorless instead on the rear standard, yet retaining the aperture control for the Contax lenses, or even remove the Contax mount from the front standard and use other lenses with the Contax backs and focal plane shutter, or with a mirrorless....
    Last edited by T.Dascalos; 13th December 2015 at 04:07. Reason: grammar mistakes

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    Re: Hassy HCD lens image circle

    Quote Originally Posted by T.Dascalos View Post
    The solution I ended up to do the above, is to chose the Rollei X-Act as my view camera (because the body - other than being small - has been designed as to be used with MF lenses and MFDB and can allow for one to use a mirrorless on the rear standard) and then use a S/H Contax 645 body from which I will remove the mount and CPU contacts and integrate them on the removable disc of the front standard... Then I'll have the back plate of the camera body removed (with the CPU contacts, the focal plane shutter and the hinges for the MFDB) and integrate them on the removable disc of the rear standard. Then, I'll retain the rest of the body, attach it to the back of the x-act2's rail and have extension cables from the remains of the body that will connect back the CPU interface (via multi-pin plugs) to the front and rear standard.... For optical VF, I'll be converting a film back that will have a screen where the film plane should be and use a the Hartblei chimney finder for loop as to be able to just attach the film back instead of the MFDB, or use the MFDB's LV...

    Don't forget to post pictures of the final product. I am sure we will all be literally thrilled.

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    Re: Hassy HCD lens image circle

    Quote Originally Posted by jerome_m View Post
    Don't forget to post pictures of the final product. I am sure we will all be literally thrilled.
    I will Jerome... I will be posting the whole process with pictures step by step...

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    Re: Hassy HCD lens image circle

    Quote Originally Posted by T.Dascalos View Post
    I will Jerome... I will be posting the whole process with pictures step by step...
    I can't wait to see the first picture.

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    Re: Hassy HCD lens image circle

    Quote Originally Posted by jerome_m View Post
    I can't wait to see the first picture.
    Just got the xAct2 in my possession Jerome... Do you want a picture of that? I'm sure you can find plenty on web on how it looks... Other than that, I have a C645 body already in my technician's workshop... Now we can all relax for Christmas and then start again what (I'm sure) will be a great subject.... Other than that, the xAct2 is a really small camera (more related to Actus or Universallis - although not than small - but significantly smaller than a P3 or an Ultima), it's sturdiness though is comparable to a P3 and movement precision is right among the top available.... There is a small drawback as the camera doesn't offer center (zero) "clicks" in any of its adjustments, but (unless if one is careless) this can't be a problem....
    The impressive thing with it is that the front standard plate can be as close to the rear standard as to squeeze the bellows to only a few millimeters (very important as it leaves huge tolerances for lenses to be compatible...). Another thing to consider is that the mounting "disks" of both the front standard and rear standard are compatible with Novoflex Balpro T-S.... So one has an (extremely wide) variety of mounts available for lenses and rear camera mounts already... and this is at "Novoflex prices"... nothing to do with Arca pricing....
    Last edited by T.Dascalos; 13th December 2015 at 14:21. Reason: grammar

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    Re: Hassy HCD lens image circle

    Quote Originally Posted by Miller View Post
    When I use the 28 mm with a film back, the negatives show dark corners.
    I was told that HCD essentially has only about 60mm image circle, hence I will not get much shift on the FPS + Adaptor setup.

    A shame really, I was hoping that I would get a very compact 1 lens shift kit...

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    Re: Hassy HCD lens image circle

    I know this is an old thread, but I'm curious if T.Dascalos ever finished the Contax / Rollei X-ACT 2 project he described above.

    It appears this was his last post here and I've had no luck finding any more info about it.

    The reason I'm curious is because I have recently done something similar myself, except I used a Toyo VX23D as the basis for my project and a Sony A7R body in place of a digital back. (I'll eventually get around to mounting my P30+ on it as well -- because I do mostly long-exposure, nighttime photography, a shutter isn't necessary for my purposes -- but based upon my past experience with using it on an earlier version of this camera several years ago, I'm not very optimistic about its performance thanks to its use of micro-lenses):





    FYI, the next steps of this project are to add the ability to remotely control the electronic apertures of the lenses (I modified a Contax 645 extension tube to serve as the lens mount in order to get access to the pins on the lens) and to also adapt it for the Contax N 17-35/f2.8 zoom (ditto.) As he (she?) pointed out above, the image circle with zoom lenses typically increases as they zoom toward their longer end and that's definitely the case with this lens, because it has a few mm of movements on a 24x36 sensor available at 17mm and plenty of room for movements by 21mm.

    Anyway, I was just curious to compare notes, so if anybody can update me or has any leads on this, I'd love a pointer ... thanks!

    JG
    Last edited by Audii-Dudii; 21st August 2016 at 08:27. Reason: fix typo

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    Re: Hassy HCD lens image circle

    Audii Dudii, the conversion looks great... Just wondering how you change the aperture of the Contax 645 lens? Are you presetting it somehow?

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    Re: Hassy HCD lens image circle

    Quote Originally Posted by mandonbossi View Post
    Audii Dudii, the conversion looks great... Just wondering how you change the aperture of the Contax 645 lens? Are you presetting it somehow?
    Yes, for the moment, I'm using the lenses preset. Although it's slightly clumsy, for the type of photography I primarily do -- long-exposure, nighttime stuff on a tripod -- it's a very workable method (especially since most of the lenses are a bit on the slow side, so opening up them up to compose and focus doesn't admit as much additional light as a faster lens does, thus reducing the benefits of doing so) and I used these lenses on my A7r for more than a year with considerable success.

    However, one way or another, I ultimately intend to control the electronic apertures remotely, while the lenses are still mounted on the Toyo. To this end, I used a Contax 645 26mm auto extension tube to provide the lens mount (and since this photo was taken, I have subsequently shortened it a few mm to reduce its thickness to 11.5 mm):



    I specifically used the 26mm version, because it's identical to the 13mm version, except that it adds a 13mm spacer between the camera body and lens mounts, plus it uses wires to connect the pins on both sides, whereas the 13mm version connects the pins together via a circuit board, which is much more difficult to hack. (The 52mm version is identical to the 26mm version, except it uses a thicker spacer and longer wires.)

    I am still waiting on the connectors I ordered from China via eBay, but my plan is to either attach them to a remote Contax body (via the camera body mount on other side of the auto extension tube that was left over when I salvaged the lens mount side) or to adapt a Fringer adapter to serve the same purpose. Of the two, the remote camera body approach will be easier, because unlike the Kipon adapter for the Contax N lenses, which uses ribbon cables to connect the pins on both sides to the central circuit board (thus making it easy to hack), the Fringer adapter, similar to the 13mm auto extension tube, connects the pins directly to the central circuit board (making it more difficult to hack.)

    I'm still undecided at this point as to which method I will use, but just in case, to make more room between the two standards should I decide to go with the Fringer adapter approach (I have on sitting next to my keyboard as I type this!), I recently redid the lens board using the scarce, 24.9mm recessed board Toyo once offered instead of the 12.5mm recessed board that is currently available. Recessing the lens by an additional 12.4mm requires the standards to spread further apart by a corresponding amount, creating more room inside the bellows to hold the guts of the Fringer adapter, should I decide to go this way. (In theory, this will also make it possible to autofocus the lenses ... imagine that: A view camera with autofocus lenses!)

    FYI, I am also planning to use at least the Contax N 17-35/f2.8 zoom on this camera, because I prefer a wider perspective to a longer one and I rarely use any lens longer than 55mm. The image circle this lens projects is surprisingly large (there's only a few mm available for movements at 17mm, but by 21mm, the image circle has grown considerably, and by 35mm, it almost covers a 6x6 cm frame!)

    Contax N 17-35/f2.8 zoom image circle at 21mm:



    Contax N 17-5/f2.8 zoom image circle at 35mm:



    Note: The grid lines are 10mm apart, so you can see there is significant coverage available at these focal lengths and every one in between them. The image quality seems to be pretty good, too, although there is sometimes noticeable smearing in the corners at 17mm (which the Kolari thin-filter mod goes a long way toward eliminating, btw) but that largely disappears by 19-20mm and as you can see, any magenta-green color shifts are minimal as well. That said, don't read too much into IQ with regard to these photos, because I free-lensed them, holding the back of the lens against a flat lens board. As such, the focus plane may not have been perfectly parallel to the sensor.

    Using this lens with movements is the primary reason I built this camera -- it has been a favorite of mine, distortions and all, since I bought it more than a decade ago -- and being able to use my Contax 645 lenses as well is just a nice bonus. Unfortunately, bringing the two standards together close enough to focus it at infinity (the Contax N lens flange-to-sensor distance is 48mm versus 64mm for the Contax 645 lenses) will make it difficult to stuff the guts of the Fringer adapter inside the bellows between them, so I will probably use the guts of the Kipon adapter instead -- Yes, I have one of these sitting next to my keyboard as well -- should I decide against using an external body.

    I'm fairly certain I answered your question somewhere above, but if not (or you have any more questions), feel free to send me a PM.

    P.S.: I dropped my A7r body earlier today and now it doesn't work. This makes not one, but two broken A7r bodies I now own, and with my annual insurance premiums and property tax bills coming due in September and October, respectively, it will be several months yet before I am comfortable spending money to buy a replacement or have this latest broken one repaired, if possible. In the meantime, I'm going to use my Fuji X-Pro 1 -- it's just collecting dust otherwise and something is better than nothing, eh? -- and have started work on the adapter / mounting plate for it this afternoon. Because of its 1.5X crop factor, my 645 lenses will now be too long for my taste and preference, so I'm going to focus my attention on the Contax N 17-35/f2.8 for now, as I expect to be able to get by with its effective focal length of 25-52mm. On the positive side, the amount of movement available from this lens just increased significantly! (sigh)
    Last edited by Audii-Dudii; 23rd August 2016 at 17:45.

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    Re: Hassy HCD lens image circle

    Awesome, thanks so much! Yep, it has been answered in there somewhere

    I was able to test out the Contax 645 35mm on Mirex shift adapter but I ran into vignetting from the adapter itself before running into issues with image circle..

    Am really hoping that Cambo will create a lensboard for the Actus system that incorporates the C645 lenses... That would be awesome!

    Please keep us updated if you have any luck getting the Contax 645 lens and other body to communicate with one another...

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    Re: Hassy HCD lens image circle

    Kimyeesan,
    I have also been curious to know the image circle of these Hasselblad lenses and am quite surprised that Alpa does not provide this information, given it is directly related to a product they are selling...


    I remember reading that the Hasselblad lenses are able to be used with the leaf shutter lenses incorporated in them.. That would be very cool indeed..

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    Re: Hassy HCD lens image circle

    Quote Originally Posted by mandonbossi View Post
    Please keep us updated if you have any luck getting the Contax 645 lens and other body to communicate with one another...
    I've already achieved this by hooking everything together on my workbench, so all that remains now is to incorporate all of it into the camera, which should not be too difficult.

    Famous last words, I know...

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    Re: Hassy HCD lens image circle

    Best of luck with it!

    Please keep us informed..

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