Obscure Red optics question RPZ 50-150

[Mark Whittier]

I'm trying to repair a Red 50-150 zoom. It has damaged front element, otherwise great shape. Red says the lens is too old, they don't carry parts and declined to service. I'm hoping to unravel some 'mythology' before attempting a fix with Duclos. They're willing to try if I can provide the correct parts. Rumor has it optics came from Sigma 50-150 stills lens (denied by Red) with housing/mechanics built in UK by Cooke (denied by Cooke - though it has i-electronics contacts, icon and signature yellow markings) Poor, unwanted orphans these early Red Pro zooms!

I want to buy a used sigma to cannibalize the front element (discontinued lens, no factory parts) and hope to get the donor with optics/coatings/color cast as close to original as possible. We already have a good 18-50mm, so it's like an RPZ orphanage here. Except the orphans provide acceptably good-looking, cheap PL mount coverage from 18-150mm.

If you're still reading, you may know the answer to my question -- which version of Sigma 50-150 should I look for? The RPZ is an early example with yellow markings (2008-2010?) -- and my basic understanding of donor options from google research:

- Sigma EX AP DC HSM 50-150 F/2.8 (mk1) - circa 2006-2007 - lots of alphabet soup with these model names
- Sigma EX APO DC HSM 50-150 F/2.8 II (mk2) - circa 2008-2012, slight difference in length, same design and optical elements, possibly a change to coatings? Sigma themselves were very opaque about Lens I -vs- Lens II differences at the time. This model is my best guess since it was mfg around the same time as the RPZ?
- Sigma EX DC OS HSM 50-150 F/2.8 (mk3) - 2012-now discontinued - added optical stabilization, re-designed, different number of elements, larger diameter, bigger, heavier lens, most likely not RPZ optics donor. Red specs for 50-150 state 39.4" minimum focusing distance, same as mk1&2 Sigmas; mk3 Sigma is 31" min focus.

If you can help I would appreciate it since Sigma 50-150's go for $500+ in good shape. It shouldn't matter what mount-type since I just need the front element (right?) But probably look for EF so we can use it un-cinevised if the experiment fails. If anyone knows for certain about this obscure detail I will send $50 starbucks card for first correct answer w/Sigma model# (if it differs from above). Rumors, speculation and hearsay are also welcome (but uncompensated). If you love to repair old Red zooms and have spares on-hand PM me (ha!) Apologize for anything optically-inept in the post, I'm a PD, not a DP. Can barely turn on my own camera. Great forum you have here, keep up the good work, etc.
:svengo::svengo::svengo::svengo:

 

[Scot Yount]

What makes you think they were made by sigma?

 

[Mark Whittier]

Thx for your reply Scot. Mostly speculation and educated opinions from archival posts on Reduser. There's some evidence with seemingly identical optical specs, comparable dimensions and light weight for a tele zoom. Also descriptions of subjective look or color cast of the lens 'to the yellow side of warm' also characterized by the sigma. But I don't have a great deal of expertise on lenses.

When I e-mailed Duclos about the repair they confirmed optics came from sigma, but can't get spare parts for RPZ or sigma 50-150. They couldn't confirm which model the elements came from -- so caveat is I'm on my own until they have the RPZ and donor lens on their bench, to know for sure if they can do the swap. They seemed like the ones to call after Red since they re-house a lot of still lenses and are respected for quality service.

 

[sander kamp]

In case of the 50-150 it's a bit difficult to see which was the base lens. I have the 17-50 and it is clear to see the lens that is inside, which might be a Tamron.

Is there a way to remove the front shade of the 50-150? Maybe then you get some clues as to what's inside.

 

[Mark Whittier]

When the lens arrives from France (gulp) I will have a better look. E-bay photos probably scared off any level-headed bidders hmy:

 

[Scot Yount]

In case of the 50-150 it's a bit difficult to see which was the base lens. I have the 17-50 and it is clear to see the lens that is inside, which might be a Tamron.

Bingo.

 

[Mark Whittier]

Looks like Tamron mfg 17-50mm, 70-200, 150-300, didn't find a 50-150? Samsung markets 50-150 f2.8 w OIS - min focus 28" RPZ 50-150 min focus 39.4"

 

[John Guarino]

I have a Red 50-150 that I recently sent to Duclos but they couldn't fix becaus it has some serious de-centration issues, the image flares badly to one side. Are you still looking to repair yours?