18-50 zoom problem...or not

[M. Bergeron]

Hi,

My Red Zoom 18-50 has some sort of play in the zoom mechanism. Every time I change zoom direction, the image shifts a little. Before Red, I worked with and owned JVCs, DVX100 and HVX200 and never had this kind of issue.

Here's a video:
http://www.soupmedia.net/lensplay.mov

I sent the lens to Red for checking and they replied that "it was determined that the lens was within tolerance". I don't know what I should expect from a lens like this one and would like an advice.

Can someone please enlighten me on this?

Thanks for helping.

[Jeff Mustaman]

That sucks!! I don't have any experience yet with the RED lens, but this doesn't seem within tolerance.. I thought that you moved to camera because you where zooming first! (you didn't right, it was completly still?)

Although the price point of the lens is really great, it's still an expensive lens where you do expect good quality, and because it's from RED you even expect top quality, so I don't think this is something that is normal, I never seen it on other footage recorded with the 18-50.

[M. Bergeron]

It was still. I did the in/out zoom many times to make sure I was not making a mistake. At certain focal length the shift is less obvious but still there.

[Jeff Mustaman]

I would like to know, why RED said that this was within tolerance, there is probably a good explanation for it.. RED team?

[Brian D. Goff]

Hi,

My Red Zoom 18-50 has some sort of play in the zoom mechanism. Every time I change zoom direction, the image shifts a little. Before Red, I worked with and owned JVCs, DVX100 and HVX200 and never had this kind of issue.

Here's a video:
http://www.soupmedia.net/lensplay.mov

I sent the lens to Red for checking and they replied that "it was determined that the lens was within tolerance". I don't know what I should expect from a lens like this one and would like an advice.

Can someone please enlighten me on this?

Thanks for helping.

Is your PL mount tight? Did you tighten the back-focus ring on the RED lens mount. If you loosened it to make back-focus and forgot to tighten it, that could be the problem.

[M. Bergeron]

It was very tight. I double checked the basic stuff twice.

It really seem to come from the zoom ring mechanism. I cannot redo it now since my lens is at Red's. I'm waiting for a more thorough answer from them on this.

I just wanted to see if it was normal. It appears not to be.

[Matthew Duclos]

Search the forum for these issues. You will find that it is the nature of the beast. With a lens like that, it can't be helped unless RED put a LOT more time and design into the mechanics of the 18-50. I would consider the RED 18-50 more of a variable prime lens. Like I said, just search the forums here. I've posted quite a bit of material. Some of which has been removed ;)

[Matthew Duclos]

Just so that I'm being neutral here...
The mechanics that RED have added are quite nice. The focus runs on a dual cam mechanism and the zoom mostly uses the original lens mechanics. But they did quite well working with what they had.

[Jeff Mustaman]

I did read some problems with the zoom, but never imagined it would look like this.

[Matthew Duclos]

I watched the video clip... Thats about what I would expect to see when bench tested on a projector with that lens. Sorry.

[Matthew Verkler]

I'll just echo what Matthew said. It's been well-discussed on this forum that the Red 18-50 is best as a variable prime. If you understand and accept that caveat, this lens makes good images. If you want smooth zooms that hold focus precisely throughout the range, then another lens would be more appropriate. I expect the upcoming Red 18-85 to be GREAT.

Having said that, I really like the Red 18-50 for its size, weight, and image characteristics. Definitely glad I got it, and can't wait for my 50-150 to arrive. The current Red 300mm is very good; I don't feel like there are any compromises when I use it. I have a reservation for the 18-85 as well.