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Guest kds315

[UV] Reflected UV - handheld

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Guest kds315

Well, today a long expected package arrived, just in time to make good use of the great weather we currently have here.

But first a little about the Odyssee that Panasonic LUMIX GH1 camera took:

First conversion, done by a very professional and well reputed company (name won't be mentioned). As I have the filters now to measure, here the results of their "full spectrum UVI conversion"

large.jpg

Although they highlight their ability to replace the shaker glass and have the dust shaker mechanism still working, what I got was obviously the orginal shaker glass in place (bright pink line), that combined with the replacement UVI filter (pink line), resulted in the overall transmission of the UVI converted camera (green line) I got. No wonder I got these extremely long exposure times (>15sec) for UV and also IR. I sent the camera back, but got it back in same state, "all in order".

Then to my rescue, I found another professional where I discussed these issue and immediately knew I would be in good hands. Both UVI filter and shaker glass were carefully removed and replaced after some discussion with best available silica glass of suitable thickness (rose line) for the internal filter and the dust shaker glass. Alternatively some borofloat glass could have been used (teal line), but I went for the better. For comparison the previously inserted UVI filter is also shown (violet line). [My spectrometer is not even good enough to measure that silica glass, as it transmits flat >80% beyond 300nm].

Now the overall transmission looks like that:

large.jpg

So now my camera is just limited by its life NMOS sensor response, whose limits still needs to be tested out (so keep tuned in here on NG...).

Eager to know what the results would be, I took a few test shots under various conditions (sun, half sun, shade) and compared the results:

As it is a full spectrum converted camera, it needs a filter to shoot correct VIS shots. I use a Baader UV/IR Cut filter and Schott BG38 for that (both about replicate the filters it had in before). For UV I use the excellent Baader-U filter. Difference in exposure VIS to UV was 6.5-7 EV (D200 UVIR needs 8-10EV for comparison).

In camera whitebalance was done using my ReflectionDisc which worked perfectly and immediately delivered well balanced UV shots.

But the best is its ability to use high ISO values (I used up to ISO1600 for handheld shots) and a perfectly clear working, bright lifeview, also with Baader-U filter attached to the taking lens (which waves goodbye focusing problems caused by most lenses having color shift).

A few handheld examples, in camera jpgs, unmodified and uncropped 14Mp images, just resized, shot using ISO1600, custom WB (using my PFTE ReflectivityDisc), CERCO 94mm lens, Baader-U filter and 1/5-1/40sec exposure times (good that I have a steady hand):

5739986681_a231fc9081_b.jpg

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5739986397_2eea48fe64_b.jpg

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5739986171_58e0ee70df_b.jpg

5739986107_7d07223be5_b.jpg

5739985631_d0c68b826b_b.jpg

5740536768_ba09992fc1_b.jpg

nuff for now, more later...

.

Edited by kds315

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Guest kds315

Using a tripod certainly helps a lot, one example

5740910218_ff3b25759f_b.jpg

5740910166_8d8775e210_b.jpg

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Guest Alex H

Looks great, Klaus. I am glad everything worked out well the second time.

What were the exposure settings (F-stop and shutter speed) for some of the hand-held shots?

With my NEX-3 I often go as high as ISO 6400 (like today, when it was very windy). I do have to do some serious noise reduction afterwards, but for me it is better to have sharp and noisy picture, than fuzzy and clean. But then I can use 1/40-1/60 sec with F/5/6-F/8 in bright sunlight.

Looking forward to see more pictures

Alex

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Guest kds315

I had mentioned that Alex: 1/5 - 1/40sec at ISO1600, f5.6

I haven't used higher ISO values yet, but I will eventually.

I haven't used any noise reduction or PP on the shots shown.

The still on tripod was exposed as:

Exposure time: 1/2.50, F-stop: 5.6, ISO speed: 640 in shadow for the UV shot

Exposure time: 1/800, F-stop: 5.6, ISO speed: 640 in shadow for the VIS shot

Here just for fun, a street scene shot from my balcony

post-75-0-97160600-1305921309_thumb.jpg

Edited by kds315

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Guest Alex H

Sorry, Klaus, that I missed the exposure data. I went straight to the pictures!

Alex

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Guest kds315

No worries, I would have done the same!!

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Guest overmywaders

Klaus,

Wonderful! Isn't Liveview so much easier?

I used the AVCHD setting for some videos. While the videos were excellent in the original format, by the time I had converted them to play on the computer they had lost much of their clarity and were noisy. I will use the Motion JPEG format from now on and go straight to the computer.

Regards,

Reed

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Guest kds315

Well, since I have quite a few UV corrected lenses, it is not an issue and I have lifeview for UV since

years using my Olympus cameras, but yes, it is a step forward indeed, especially the increase in sensitivity

at rather low noise.

I'm just playing around with UV video as I did that for BBC before at a substantially higher effort, so that

is another step forward. AVCHD does not really work well on my older PC and eats up memory on card + PC, but

for serious professional productions, it's a must have.

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Congratulations on the succesful (at last) modification,Klaus!

Really fascinating to watch this, and on top of all this: a UV video. :drinks:

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Guest kds315

Thanks Bjørn, yes that will be a very valuable tool for future work!

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Guest brianc1959

Why not reveal the name(s) of the conversion companies you used here?

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Guest oojala

Thanks for a very interesting post and great that everything ended well after the first unsatisfactory conversion!

I find that the Panasonic micro 4/3s are very nice for certain kind of macro work, even a slightly smaller tripod usually suffices due to the small size of the cameras. Nice to know that one could potentially be modified for non-visible work also.

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Guest kds315

Why not reveal the name(s) of the conversion companies you used here?

Just legal reasons for now. Will be sorted out soon.

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Guest kds315

Calibrated my Bee Vision filter today to that GH1-UVIR. Using my ReflectionDisc that was a breeze to do.

original.jpg

Edited by kds315

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I like the color of the last image. Very nice!

By the way, have you seen Vivek's UV-video?

Edited by Akira

"The eye is blind if the mind is absent." - Confucius

http://www.flickr.com/photos/akiraphoto/

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Guest kds315

Thanks Akira. No I haven't - where is it?

Have you seen mine I made for BBC London?

And my test videos HERE on my BLOG ?

Edited by kds315

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Guest kds315

I had a look at them. Too bad no tripod was used, very shaky all of them, but

nevertheless proves that the camera he used (?) works in UV.

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Bob, thanks for the follow-up. Yup, these are the videos I was referring to.

Klaus, they are just preliminary shots, as mentioned there. Is the BBC movie the one with the credits for you and Bjørn at the end? If so, I've already enjoyed it.


"The eye is blind if the mind is absent." - Confucius

http://www.flickr.com/photos/akiraphoto/

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I've just place the order of the DVD at amazon.co.uk. Luckily Japan belongs to the "region 2", too. :pleasantry:

Edited by Akira

"The eye is blind if the mind is absent." - Confucius

http://www.flickr.com/photos/akiraphoto/

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Guest kds315

Hope you enjoy it! We filmed so much more in UV (spiders etc) but due to time constraints

only a fraction made it to the final cut.

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This last photo is wonderful! Great that it finally worked out well with your conversion.

Chris


Never mind the words ... just hum along and keep on going...

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