Panasonic Lumix DMC G3 Camera

[colinbm]

Hi Alex

We cross posted.

The G3 kit 14-45mm lens is sharper in the corners.

Cheers

Col

[Alex H]

I wish there was similar kit zoom for NEX...

[JCDowdy]

My first pass with the G3 kit zoom doesn't seem close to that.

However, lacking the internal quartz of Col's conversion I cannot say for certain.

Truth is, it had not occurred to me to even try.

[colinbm]

Two UV shots today with the Mayfair Crystar 35mm f3.5 & the G3 kit 14-45mm lens at 39mm.

Both individually custom white balanced & with the BaaderU2 filter.

Col

 

Mayfair Crystar 35mm f3.5.

 

G3 kit lens 14-45mm at 39mm.

[Alex H]

Setting both to same WB will show the differences better. What was the aperture set to on Mayfair Crystar?

[kds315]

Yes, that would have been my comment, too. A rather meaningless comparison. And then not even the same image content. Hmm, at least the focal length is different :)

[colinbm]

Thanks Alex

The Crystar 35mm was at f11.

When I looked at the PhotoNinja colour temps for both of these shots, they were very different. The Crystar 35mm was 2000k (where I would expect it to be) & the G3 kit lens 14-45mm was 15000k.

I don't know why they are so different ?

So if I use the same CWB for both shot with both lenses, will that be a fair comparison ?

Cheers

Col

[colinbm]

Yes, that would have been my comment, too. A rather meaningless comparison. And then not even the same image content. Hmm, at least the focal length is different :)

 

What is there for me to learn, from a comment like that Klaus ?

Col

[Alex H]

Thanks Alex

The Crystar 35mm was at f11.

When I looked at the PhotoNinja colour temps for both of these shots, they were very different. The Crystar 35mm was 2000k (where I would expect it to be) & the G3 kit lens 14-45mm was 15000k.

I don't know why they are so different ?

So if I use the same CWB for both shot with both lenses, will that be a fair comparison ?

Cheers

Col

 

The color temperatures are different because these two lenses have different transmission across the range. If you set both pictures to the same WB, the differences will be much more obvious. Also, I would recommend to use flowers for such comparison, the ones that are represented with false yellow in UV pictures, because the scene that you have shot does not have any objects that will reflect UV in 340-350 nm range.

[kds315]

What is there for me to learn, from a comment like that Klaus ?

Col

 

Make it comparable: same aperture, same focal length, same ISO and white balance setting, same situation (light especially). Then compare the differences: exposure time , histogram for instance

 

And Alex is very right, use a target which allows to really compare UV shots reaching deep enough into UV. Do you have Zinnia flowers in AUS? Their pattern reach to 300nm and beyond (Mexican Zinnias that is)

[colinbm]

Thanks Alex

I'll set that up, in a few days.

I was just out & about today in my local park taking some natural landscapes, but it was a bit breezy & they were only showing black & white UV.

I did a couple of urban shots to get some violet into the scene.

Cheers

Col

[Andrea B.]

....if the PenF 20mm f3.5 is considered, 'usable', for UV photography, then perhaps the G3's kit lens is 'usable' for UV too ?

 

Well, let's remember that you can use almost any lens for UV shooting with long enough exposures. My kit lens from the GH1 gives quite serviceable UV photos - the first Panasonic 14-45 G-Vario zoomer. (This 14-45 was changed in later editions.)

 

However, we search for the simpler, uncoated lenses in order to decrease exposure times and increase UV transmission.

[Andrea B.]

the same WB

 

same aperture, same focal length, same ISO and white balance setting, same situation (light especially). Then compare the differences: exposure time , histogram

 

Look at my Kaligar 35/3.5 and Pentax 35/4.0 test for examples. :D

 

********

 

Mexican Zinnias

 

And Bidens too, yes?

 

********

 

I'm not entirely sure about making comparisons using the same white balance.

 

One could make the case that using a calibrated white balance for each lens would provide a comparison more useful for the way one would actually use the lens for shooting ?? There might be tints and casts to colour which might have nothing to do with UV transmission but which might possibly be from different glass types and/or coatings. Notice I use the word 'might'.

 

Any comments on this thought about calibrated WB for each lens ??

[Alex H]

There might be tints and casts to colour which might have nothing to do with UV transmission but which might possibly be from different glass types and/or coatings. Notice I use the word 'might'.

 

How else the glass type or coating have any impact on the recorded image if not by affecting the transmission of light through it? (not accounting for flare)

[Andrea B.]

Well, I don't know how to phrase it properly. :D (Too many wild ideas, not enough descriptive vocabulary, laughing...)

 

I'm extrapolating from the visible case where we sometimes see minor colour casts from coatings/glass which have had no effect on light transmission -- two different lenses, same exposure for given scene, but requiring slightly different white balance.

 

But the larger point was --- perhaps we should test lenses as we are actually going to be using them? And that would include white balance on a per-lens basis rather than using a generic in-camera white balance? Just raising the point for discussion.

 

On a side note: Unfortunately, that is a moot point for me and the D600 which will not properly white balance in-camera in UV. I have to always shoot with the same (inaccurate) WB and make a session record of standards and colour patches so I can retrieve the accurate WB later in the editor.

[Alex H]

I'm extrapolating from the visible case where we sometimes see minor colour casts from coatings/glass which have had no effect on light transmission -- two different lenses, same exposure for given scene, but requiring slightly different white balance.

 

That's because differnt coatings and glass types transmit light (visible or uv) differently. The lens or coating that cuts a bit more of blue will produce "warmer" images and the lens that cuts more red will produce the "colder" images. Just like one and the same lens will produce different color cast or different WB if the composition of light source is different (sun vs. incadescent vs. fluorescent tubes). There is nothing more to it, just transmission.

 

But the larger point was --- perhaps we should test lenses as we are actually going to be using them? And that would include white balance on a per-lens basis rather than using a generic in-camera white balance? Just raising the point for discussion.

 

Not when you are comparing physical properties. If you compare lens transmission, you would want to exclude all variables as much as possible and WB is one of them. One can avoid dealing with WB by using RAWDigger for example.

 

We know that R, G and B photodiodes have different "sensitivity" for the same wavelengs of UV (which is mostly determined by the transmission of dyes of CFA). For example if red photodiode is 5 times (just making up the numbers) more "sensitive" to the same amount of UV comparing to blue photodiode, and than signal from red photodiode is amplified twice as much as the signal from blue photodiode, our custom WB would be used to correct that. The difference in sensitivity of different photodiodes most probably also changes across the UV range. WB and profiling is used to compensate for that to a certain extent. Surely, WB for the image that captures 340-390 nm will adjust data very differently than the WB for the image that captures only 360-390 nm.

 

Having actual sensor sensitivity data for each channel across the UV spectrum will be extremely helpful to really understand what is going on, and not just guesstimate.

 

If you just want to compare pictorial properties of lenses than yes, I would compare the resulting pictures produced in the same way as I would actually be using them.

[Andrea B.]

There is nothing more to it, just transmission.

 

Yes, you are correct !! I should have been thinking about channels. :D

 

****

 

OK, there's the vocabulary: comparing the physical properties versus comparing the pictoral properties.

 

I suppose for a typical casual UV shooter that the practical, pictoral comparison is the most useful. But for a laboratory/scientific/forensic setting, there is a mandate to discover the technical, physical properties of the lens.

 

And White balance can be a Red herring indeed. I've been quite amazed by the Raw Digger raw composites.

 

On a contemplative note, I have some very lovely dedicated UV lenses like the UV-Nikkor. But I sometimes wonder if there is any real reason for me to have such a lens? For example, I probably will never make use of the UV-Nikkor's ability to transmit down to 200 nm. I certainly do appreciate the UV-Nikkor's fine photographic qualities, don't get me wrong. Oh well. Ignoring "need", I pursue this UV photography thing as deeply as I can just out of sheer interest - and geekiness too, no doubt.

[colinbm]

I braved a Bee Vision flower shoot today, with the G3, there was a slight breeze & nice sunlight.

I wanted to enhance the UV with an MTE U301 UV 365nm flashlight, & I was pleasantly surprised.

The MTE brought out the colours & contrast nicely, of the filter stack, BG3 + S8612, & the CWB on a Teflon block.

Panasonic G3 camera with a Mayfair Crystar 35mm f3.5 lens at f16, ISO200 at 1/5th second.

Cheers

Col

 

Allamanda flower, in Enhanced Bee Vision.

[Andrea B.]

Looks like you are up and running, Col. The G3 will be so cool to use for various experiments. Hope you enjoy it!! :)

 

To clarify, you shoot the in-camera white balance under the BG3 + S8612 stack - but with or without the 365nm flashlight?

 

What do you use in Photo Ninja to preserve the in-camera wb?

[JCDowdy]

What do you use in Photo Ninja to preserve the in-camera wb?

 

Under Color correction, White balance, Mode = From camera.

[colinbm]

Thanks Andrea & John

Yes the CWB is taken with the filter stack, & off the block of Teflon, under sunlight. With or without the MTE didn't seem to matter.

I don't know how to confirm it, but I think that PhotoNinja is limited in WB range, Kelvin degrees, compared to the Panasonic G3.

As John said, "Under Color correction, White balance, Mode = From camera."

If I change this setting in PhotoNinja & try to get it back again, I can't, I have to re-load the image.

Again in PSE11 it can't handle this CWB either.

Cheers

Col

[colinbm]

Another day & another filter test.........

Enhanced Bee Vision, with a UG5 & S8612 stack, CWB off a block of Teflon, & enhanced with the MTE U301 UV 365NM flashlight.

Still breezy & overcast today.

Panasonic G3 camera with a Mayfair Crystar 35mm f3.5 lens at f16, ISO200 at 2 seconds.

Cheers

Col

 

Allamanda flower, in Enhanced Bee Vision.

[Alex H]

Nice results, Colin. What confuses me if the therm "enhanced" in the connection of "bee vision". What would be the reasoning to use it. Sorry, I am not a native English speaker...

[colinbm]

Thanks Alex

The centre flower is illuminated with the MTE U301 UV 365nm flashlight.

Col

[Alex H]

OK, thanks.