CFV-39 & 30MM Lens

[rashed_s]

Now I have my 30MM Lens, which format is the most suitable to use with the 30MM lens and the CFV-39 digital back, the square format or

the horizontal one and how much of the fish eye effect going to be there comparing it to the use of film.

 

Thank you and all of the best.

[leighb]

<p>Why don't you try both and report back? Experimentation costs virtually nothing.</p>

<p>Since the square format is just a crop of the rectangular, so you need only shoot the latter then look at the portion of the image in the middle.<br>

- Leigh</p>

 

[diegobuono]

<p>Hi,<br>

there was a field of view camparison on the Zeiss web site but is gone.<br>

You can print an image taken with the 30mm and draw on it the rectangle (or square) of the same dimensione of the sensor (49,1 X 36,7 or 36,7 X 36,7 if you want it square).<br>

If you print the picture larger than 5,5 cm X 5,5cm do the math consequently; i.e. on a picture printed 30cm X 30cm draw in the center a rectangle 26,81cm X 20,04cm.<br>

Here some sample image<br>

<a href="http://www.google.it/search?hl=it&q=images%20taken%20with%20Hasselblad%2030mm&gs_sm=e&gs_upl=1516l10860l0l11234l33l30l0l16l16l1l406l3436l2-5.4.2l11l0&um=1&ie=UTF-8&tbm=isch&source=og&sa=N&tab=wi">http://www.google.it/search?hl=it&q=images%20taken%20with%20Hasselblad%2030mm&gs_sm=e&gs_upl=1516l10860l0l11234l33l30l0l16l16l1l406l3436l2-5.4.2l11l0&um=1&ie=UTF-8&tbm=isch&source=og&sa=N&tab=wi</a><br>

Diego</p>

[leighb]

<p>The problem is not field of view. It's the angle of incidence of light on the sensor.</p>

<p>The sensor is not designed for use with large angles, as are experienced with short FL lenses.</p>

<p>Hasselblad specifically recommends against using the CFV-39 with the SWC cameras (39mm lens). <br>

I expect that restriction would apply to the 30mm.</p>

<p>Try it and see.</p>

<p>- Leigh</p>

 

[q.g._de_bakker]

The angle of incidence at the sensor/film is not set by the focal length, but by the distance between exit pupil and sensor/film. Distagons, including the F-Distagon, are retrofocus designs, i.e. have a relatively (compared to the focal length) large distance between exit pupil and film.<br><br>And that distance is indeed large enough not to have worries about the angle of incidence at the sensor.<br>Just to get an idea: the exit pupil position, relative to the sensor, of the unproblematic 80 mm lens set to infinity is 96.4 mm.<br>That of the 30 mm fisheye is 107.6 mm (that of the 40 mm is 96.6 mm; of the 50 mm 90.4/92.2 mm, depending on FLE or non-FLE; of the 60 mm 94.5 mm).<br>So no need to worry about the angle of incidence.

[erichiss]

<p>The Zeiss 30mm fisheye on the Rollei with the CF-39 works great so I expect it would be similar in the CFV. Note this lens has some small amount of CA both lateral and axial.</p>

[ondebanks]

<p>The CFV-39 in square-crop mode is the same sensor size as my Kodak 645M digiback.<br>

The Zeiss 30mm fisheye is the same in optical parameters (whatever about performance!) as my MC Arsat 30mm fisheye.<br>

So I can comment on that combination, through these proxies.</p>

<p>The short answer is that the fisheye effect is still there, but it is not very strong, and is easier to "hide" in many compositions, if that is the desired effect. The example below is a case where of course the barrel distortion cannot be hidden.<br>

<img src="http://img848.imageshack.us/img848/3434/homefisheye30fx03700pix.jpg" alt="" /></p>

 

<blockquote>

<p>The Zeiss 30mm fisheye on the Rollei with the CF-39 works great so I expect it would be similar in the CFV. Note this lens has some small amount of CA both lateral and axial.</p>

</blockquote>

<p>Interestingly, that is also the greatest issue with the Arsat. There is also a little spherical abberation wide open at f3.5; better at f4 and gone by f5.6.</p>

<p>Both to get a wider FOV, and to greatly reduce these aberrations, I got a Mamiya 24mm ULD fisheye a few months ago. This lens is just stunningly low in abberations on my digiback, even wide open, even at closest focus <em>and</em> wide open. The lower crop factor also preserves more of the fisheye effect. Lots of creative fun. Some examples below.</p>

 

<p> </p>

[ondebanks]

<p>Mamiya 24mm ULD fisheye images on digiback, as promised. From a single beach trip...</p>

<p><em>Look down:</em><br /> <img src="http://img215.imageshack.us/img215/23/47fb7815700pix.jpg" alt="" /></p>

<p><em>Look up:</em><br /> <img src="http://img85.imageshack.us/img85/4388/47fb7821700pix.jpg" alt="" /></p>

<p><em>Look closely (wide open):</em><br /> <img src="http://img27.imageshack.us/img27/5148/47fb7807700pix.jpg" alt="" /></p>

<p><em>Detail from last photo at 100%:</em><br /> <em><img src="http://img717.imageshack.us/img717/7321/47fb7807crop700pix.jpg" alt="" /></em><br /> Please note that Photo.net is doing some resizing of my embedded jpgs (I thought they are supposed to be 700 pixels wide?), and the interpolation is reducing their sharpness, especially the final one. If you right-click the image and choose "View Image" (in Firefox anyway), you see it as it should be. <em><br /></em></p>

[wolf_rainer_schmalfuss]

<p>Its really nice to have an digital back for the V-Hasselblad body, but, it has unfortunately not the required 56x56mm sensor size to show the full capacity of an, for example 30mm Zeiss Distagon fisheye, and the other SWA Zeiss glasses. To show the full image of the fisheye lens, unfortuntaly, the old common fashion method must be used with roll film 120/220. So, it can be figured, that the investment for an expensive Zeiss fisheye lens for the V-Hasselblad body with digital back, is not very practical in this particular case. An Kiev 88 etc. body with an 30mm ARSAT fisheye glass, would be able to do the job almost as good, and would save a lot of money!</p><div></div>

[wolf_rainer_schmalfuss]

<p>Another image shot with the WIESE Pentasix 636 and the ARSAT Zodiak 3,5/30mm fisheye.</p><div></div>

[ingemar_lampa1]

<p>I know of a sensor which covers the whole area. It usually comes in a green or yellow box and is called film. </p>