My "definitive" post on the 7-14mm "Purple Blob" Problem

jloden

Mu-43 Hall of Famer
Joined
May 15, 2012
Messages
2,696
Location
Hunterdon County, NJ
Real Name
Jay
Just for the record, I got a severe case of purple blobs shooting at a wedding last week using the Oly 17/1.8 on my E-M5. It was while the disco lights were going inside a white tent at night, meaning I was effectively shooting straight into a reflective umbrella. I'll try and post an example when I can get back to my machine, but it was not subtle at all

But it clearly nether requires a Panasonic lense on an Olympic body, nor a really wide lens.
Yep, and I've seen examples of it on the 9-18mm on the OM-D EM-5 also. It's definitely something about the EM-5 sensor, and I'm inclined to believe the current theories about the UV filter being the culprit.
 

robbie36

Mu-43 All-Pro
Joined
Sep 25, 2010
Messages
1,579
Location
Bangkok
Real Name
rob collins
Ok well I got my wratten 2a gel and I was determined to see how well it works.

So I wandered around the house until I found a reasonable instance of 'purple blobs' and took a shot....

Subscribe to see EXIF info for this image (if available)


I then added the wratten 2A gel to the back filter and took another....

Subscribe to see EXIF info for this image (if available)


Hey presto... it works.... and very well indeed.

On a related note, the Wratten 2A gel is a faint yellow, so I guess there is an issue of color cast. Now I had my camera set to auto white balance and these two shots are straight out of camera. The camera however did record the white balance slightly differently. 4500 for the photo with the purple blobs and a slightly colder 4300 for the gel photo. In other words it would seem as though the gel makes the photo slightly warmer but auto white balance simply adjusts.
 

demiian

Mu-43 Rookie
Joined
Jun 14, 2012
Messages
21
Hi guys,

So, I've stumbled upon this thread, and I'm glad to hear that there's a fix for the purple flare problem on Pana 7-14 with OM-D. However, as I'm a total noob, I have trouble understanding what the necessary pieces are. (what is a "gel" filter?) Could anybody please summarize the necessary items for me and the rest of us noobs? Much appreciated! :)
 

jloden

Mu-43 Hall of Famer
Joined
May 15, 2012
Messages
2,696
Location
Hunterdon County, NJ
Real Name
Jay
Hi guys,

So, I've stumbled upon this thread, and I'm glad to hear that there's a fix for the purple flare problem on Pana 7-14 with OM-D. However, as I'm a total noob, I have trouble understanding what the necessary pieces are. (what is a "gel" filter?) Could anybody please summarize the necessary items for me and the rest of us noobs? Much appreciated! :)
You need a rear element filter holder from the Panasonic 8mm fisheye, which can be ordered separately as part #VXQ1911 from various online sources. Most places have it marked as backordered though and I've yet to see it actually in stock anywhere. I ordered mine direct from Panasonic (Parts Ordering) and it showed up in < 2 weeks.

You also need a Wratten 2A "Pale Yellow" UV gel filter. A gel filter is just a plastic filter that you can cut to shape. In this case you install the rear element filter holder, then cut down the 2A filter to fit in the holder. That filters out some of the UV spectrum that causes the purple flare coloring. I bought my filter on ebay, but you can buy them from B&H also (Kodak 3 x 3" #2A Pale Yellow Optical Wratten 2 Filter).
 

cmpatti

Mu-43 Veteran
Joined
May 8, 2011
Messages
263
Location
Berkeley, CA
Hi guys,

So, I've stumbled upon this thread, and I'm glad to hear that there's a fix for the purple flare problem on Pana 7-14 with OM-D. However, as I'm a total noob, I have trouble understanding what the necessary pieces are. (what is a "gel" filter?) Could anybody please summarize the necessary items for me and the rest of us noobs? Much appreciated! :)
This set of instructions is pretty comprehensive: http://www.dpreview.com/forums/post/51390321. The instructions have you adding a shim between the filter and the lens mount, but I didn't find it necessary.

A "gel" filter is basically a tinted piece of thin plastic. They were commonly used in film photography, but not so much now, so may be hard to find. Try one of the big online photo stores (e.g, B&H or Adorama) or eBay. They generally come in 3x3 inch squares. You need to cut a 22mm square to fit in the rear filter holder.
 

entropicremnants

Mu-43 All-Pro
Joined
Jul 16, 2012
Messages
1,109
Real Name
John Griggs
  • Thread Starter Thread Starter
  • #67
I'm getting used to the purple blobs ... I think I'll keep them.
I've gone back over some of my prints with a purple marker trying to emulate your style with the blobs... total fail. Discount prints anyone?... :tongue:
 

robbie36

Mu-43 All-Pro
Joined
Sep 25, 2010
Messages
1,579
Location
Bangkok
Real Name
rob collins
Yep, and I've seen examples of it on the 9-18mm on the OM-D EM-5 also. It's definitely something about the EM-5 sensor, and I'm inclined to believe the current theories about the UV filter being the culprit.
Yes. that is almost certainly the case. As I understand it the Wratten 2A is simply a 'strong' UV filter. So if your lens has a threaded filter (like most do) it should be fairly easily resolved.

Simply add a glass 2a filter such as this one (which would fit the Oly 9-18) from Amazon.

Amazon.com: Tiffen 52mm Haze-2A Filter: Camera & Photo
 

jloden

Mu-43 Hall of Famer
Joined
May 15, 2012
Messages
2,696
Location
Hunterdon County, NJ
Real Name
Jay
Interesting, but not necessarily related: I just spotted some blue-purple flare in an Audi commercial. I've no idea what they filmed it on but that flare looks pretty familiar, though slightly more blue in coloring :tongue:

[ame=https://www.youtube.com/watch?v=WPkByAkAdZs]Zachary Quinto vs. Leonard Nimoy: "The Challenge" - YouTube[/ame]
 

entropicremnants

Mu-43 All-Pro
Joined
Jul 16, 2012
Messages
1,109
Real Name
John Griggs
  • Thread Starter Thread Starter
  • #71
Interesting, has anyone try to use this with an nd sheet filter?
You mean not for the purple blob problem, but just as an ND? I've been thinking about getting one to do just that. It is cheaper than the big clunky filter adapter that goes on the outside -- though not as convenient to change filters for sure.
 

Kenny

Mu-43 Regular
Joined
Sep 9, 2012
Messages
175
Location
KL Malaysia
Let me know once you tried it. Im interested to use this lens under bright sun light for video.

Sent from my GT-N7100 using Mu-43 mobile app
 

entropicremnants

Mu-43 All-Pro
Joined
Jul 16, 2012
Messages
1,109
Real Name
John Griggs
  • Thread Starter Thread Starter
  • #73
Let me know once you tried it. Im interested to use this lens under bright sun light for video.

Sent from my GT-N7100 using Mu-43 mobile app
At f/4 it's not bad if you can tolerate higher shutter speeds. I'd use it more on stills for very long shutter speeds on water shots.

I just recently used the lens on a sunny afternoon and GH1 for video and that video will be out in a week or two. I didn't need "cinematic motion blur" in a documentary video so I could shoot high shutter speeds with no difficulties though. Not sure what you're looking for exactly.

The only shot with it in my teaser is the one of the flame coming on, but that's late afternoon anyway. At the end of the fast moving sequence there is a shot looking up in to the hot air balloon and a big drum hit as the flame comes on. That's the 7-14mm in that shot. Total video is 53 seconds so it won't waste too much of your time, lol. Video was shot on a hacked GH1 at a native 23.976 fps rate with the lens wide open. The interview sequence is a 25mm f/1.4 that I screwed up using a vari-ND and too many adapters, lol. More on that another time.

There's a lot of footage in sunlight with the 7-14mm in the final edit. I used it heavily and it was a lot of fun.

[ame=https://www.youtube.com/watch?v=CVzsmXHRE6w]"Flying Patriot" Teaser - YouTube[/ame]
 

DeeJayK

Mu-43 Hall of Famer
Joined
Feb 8, 2011
Messages
3,355
Location
Pacific Northwest, USA
Real Name
Keith
great job . I would prefer a little longer time before transitions on the stills
I agree with regards the first 6 or so shots (the ones which are faded in and out), although the synchronization of the cuts with the music works well in the second half of the trailer.

Nice work, John.
 

stratokaster

Mu-43 All-Pro
Joined
Jan 4, 2011
Messages
1,573
Location
Dublin, IE
Real Name
Pavel
Just for the record, I got a severe case of purple blobs shooting at a wedding last week using the Oly 17/1.8 on my E-M5. It was while the disco lights were going inside a white tent at night, meaning I was effectively shooting straight into a reflective umbrella. I'll try and post an example when I can get back to my machine, but it was not subtle at all

But it clearly nether requires a Panasonic lense on an Olympic body, nor a really wide lens.
I strongly suspect the issue is related to the infamous 'purple blob' problem that plagued E-PL2.

Olympus seems to prefer somewhat problematic UV/IR filters for use in their cameras.
 

David A

Mu-43 All-Pro
Joined
Sep 30, 2011
Messages
1,920
Location
Brisbane, Australia
I came across this thread a day or two ago on the Luminous Landscape Lightroom forum:

Removing large flare in LR4?

The interesting suggestion was to use the purple defringing tool in Lightroom for removing purple flare blobs. I don't have the 7-14 but I took a look at a shot I took with the Olympus 17mm F/1.8 which had extremely bad flaring including a couple of purple blobs because I had shot straight into an almost mid-day sun half eclipsed by a building and the defringing tool almost totally removed the purple. Of course the flare is still evident but the purple is almost completely removed with one click using the eyedropper defringing tool.

Don't know it it will work for shots with the 7-14mm but if you're using that lens and you have Lightroom 4 or 5 it's worth a go. I know I hadn't thought of using the defringing tool for coloured blobs in flare.
 

umii

Mu-43 Regular
Joined
Aug 19, 2013
Messages
113
Location
uk
Hi All,
First post and sorry to go slightly off topic right off :)

Out of interest is this related to the issue I get every now and then videoing on my GH3 with my 12-35mm lens, if I have sun out of shot near the end of the day to the left and it's overcast I quite often get a purple flare right in the centre of shot. It's been bugging me on and off for a while. Most times it's fine it just seems to be fine filming from the same spot but every now and then it happens.

example here i shot in april (nothing flashy just a quick vid I did for a friend training not the next block buster :) but it shows the issue)

[ame=https://www.youtube.com/watch?v=klrYH6m9lls]murph for charlotte! - YouTube[/ame]

and later in the year same lens not overcast much better
[ame=https://www.youtube.com/watch?v=Ch7M3f0pxQk]Pip day 88 08/07/2013 - YouTube[/ame]

Just wondered

Mark
 
Links on this page may be to our affiliates. Sales through affiliate links may benefit this site.
Mu-43 is a fan site and not associated with Olympus, Panasonic, or other manufacturers mentioned on this site.
Forum post reactions by Twemoji: https://github.com/twitter/twemoji
Copyright © 2009-2019 Amin Forums, LLC
Top Bottom