Swapping Elements In a Hasselblad 80mm F2.8 Lens

[clark_roberts]

<p>Hi all,<br>

Is it okay to switch front and rear element groups from one lens chassis to <br>

another? I know it's a no no in a Rolleiflex TLR but maybe there a slim chance<br>

in a Hassie lens?<br>

Clark</p>

[thirteenthumbs]

<p>I don't know where you got the No No about swapping lens elements on a Rolleiflex. Any brand can be swapped <strong>IF </strong>you observe the correct precautions.<br>

Lens are rarely their marked focal length. They are usually .1mm to 3mm or 4mm either side of the marked (nominal) focal length.<br>

Lens barrels and shutters have tolerances on their dimensions. The variation is usually less than .5mm.<br>

The spacing between elements is critical and must be maintained.<br>

Swapping lens elements (individual pieces or cemented pieces) or just one cell (all elements in the front or rear barrel) is not recommended.<br>

Use a digital caliper and make careful measurements.<br>

Measure the total length of the lens.<br>

Keep any shims with the cell they were on when assembled.<br>

Remove the front cell, measure its length.<br>

Measure from the front edge of the shutter or main barrel to the front element of the rear cell.<br>

Reinstall the front cell.<br>

Remove the rear cell, measure its length.<br>

Measure from the main barrel or shutter to the rear of the front element.<br>

Remove the front cell and measure the main barrel or shutter length.<br>

Repeat for the main barrel or shutter you are transferring to.<br>

Reassemble the main barrel or shutter you are switching to to match the main barrel or shutter measurements you moved the cells from. Shims may have to be added or removed or the main barrel or shutter may have to be machined down if it is thicker. Make barrel/shutter edge measurements at the center of the lens.</p>

[clark_roberts]

<p>Okay thank you.</p>

[steve_rasmussen]

<p>"Is it okay to switch front and rear element groups from one lens chassis to <br />another? "<br>

<br>

And you want to do this because... ?</p>

[hasselblad technician]

<p>In most cases, there would be no problem with swapping the front and rear lens groups from one lens to another, assuming the two lenses are the same focal length. However, if you do this, I would strongly suggest that you have the focus checked and adjusted, if necessary, by a qualified Hasselblad technician.<br>

www.david-odess.com</p>

[brett_rogers]

<blockquote>

<p><em>I don't know where you got the No No about swapping lens elements on a Rolleiflex. Any brand can be swapped <strong>IF </strong>you observe the correct precautions.</em></p>

</blockquote>

<p>Yes, that is fine in theory, <strong>Charles</strong>, but the problem is that when this practice occurs, it is usually undertaken by ignorant or unscrupulous owners, who lack both the skills and the facilities to correctly measure and adjust the affected lenses. Further, they are usually carrying out the swap for less than altruistic reasons, Ie. to cobble together a clean looking lens, that will fetch a better selling price online, regardless of whatever optical compromises are introduced along the way. When it comes to Rollei, factory original is nearly always going to be best. Unfortunately, there is no easy way of verifying whether all parts of lenses are original prior to buying, unless a seller agrees to a full inspection by a qualified technician. In the absence of this, purchasers acquiring such a franken Rollei in good faith will be disappointed by the performance of their new camera. All things considered, much better just to discourage the practice altogether, I think. </p>

[julian_oliver_bell]

<p>Yes, done properly it works well. I had it done years ago in The Netherlands by Wilco Jansen.<br>

http://www.hasselblad-reparaties.nl/</p>

[ondebanks]

<blockquote>

<p>And you want to do this because... ?</p>

</blockquote>

<p>Hopefully Clark will reply, but my guess is that one of his lenses has clean glass in a broken shutter/barrel, while the other has scratched glass in a working shutter/barrel. </p>