Brook in UV

[StephanN]

After taking the comparison photos for this thread https://www.ultravioletphotography.com/content/index.php/topic/4088-fountain-time-dependency/ , I did manage to snap a few long-time exposures of the brook in the Pesenbachtal (sorry, no translation for this one). The photos were taken with the EL-Nikkor 80, at f/16, ISO 100, 30s (only the last one 15s, as the sun had risen high enough to shine into the valley). Processing is at a minimum, mainly conversion to bw and a bit of clarity and structure. I may get around to editing and cropping a few ones more carefully.

 

What I like is the fact that the uv-black vegetation does not distract from the water and the rocks, and the almost metallic look of the rocks is intriguing. It would have been instructive to replicate them in VIS and IR, but I didn't have time for that.

[Stefano]

The water really seems silky, almost oily too.

[Cadmium]

Stephan, Those are really beautiful photos!

[Andy Perrin]

Very pretty!

[StephanN]

The water really seems silky, almost oily too.

 

Yep, I really ought to go back and do the comparison photos with VIS and IR.

 

Stephan, Those are really beautiful photos!

 

Thanks

 

Very pretty!

 

Thank you

[colinbm]

Love the 'silky' water, I have never had any luck getting this, I guess I need more time & patience....

[StephanN]

Love the 'silky' water, I have never had any luck getting this, I guess I need more time & patience....

 

 

I was lucky, as in one spot there was a huge flat rock just inside the brock, so I took at least half of my photos from this rock. There are smaller rocks on three sides and adjusting height and angle of the tripod gave plenty of opportunities. The biggest problem is that with the naked eye everything looks very different than to a camera at an exposure time of 30 seconds, so one may miss plenty of opportunities if one is in a hurry.

[colinbm]

Thanks Stephan.....one day....

[JMC]

Lovely images - the rocks look amazing, it really shows up the surface texture. I may have missed it but what UV filter were you using Stephan?

[StephanN]

Lovely images - the rocks look amazing, it really shows up the surface texture. I may have missed it but what UV filter were you using Stephan?

 

 

Thanks, I ought to have said so.

 

I'm using my Eos 6D, converted by maxmax to b/w almost uv, so have to use on of their xnite-bp1 on the lens

[bvf]

Beautiful - better than using an ND1000 filter in the visible spectrum.

[colinbm]

Thanks, I ought to have said so.

 

I'm using my Eos 6D, converted by maxmax to b/w almost uv, so have to use on of their xnite-bp1 on the lens

 

 

The xnite-bp1 passes approx 310 - 620nm.....UV + VIS.......?

[StephanN]

Beautiful - better than using an ND1000 filter in the visible spectrum.

 

 

Thanks. Would an ordinary ND-filter work in UV? Using f/22 I could have doubled the time, but the thought of using an ND-filter didn't occur to me. I could have set the focus more selectively.

 

The xnite-bp1 passes approx 310 - 620nm.....UV + VIS.......?

 

 

Sorry, the half-uv conversion means that there is an internal filter installed, which is the X-Nite 330 , so together it gives this transmission:

 

[colinbm]

Thanks Stephan

[bvf]

Thanks. Would an ordinary ND-filter work in UV? Using f/22 I could have doubled the time, but the thought of using an ND-filter didn't occur to me. I could have set the focus more selectively.

 

 

 

I've never tried an ND filter with UV. It probably is not great at passing UV - but then that's what you're looking for. Problem might be reach into the UV spectrum, if that's important. It would be worth a try.

[Andy Perrin]

Why would you NEED a ND filter in UV? The problem is usually that we never have enough light! But anyway, my suggestion would be to do what I did with the astronomy software in the Queen Anne's Lace UVIVF thread and just take lots of images using an intervalometer then average them using the astronomy software. On the Mac I use Long Exposure Stacker (which is available in the app store) but there are many others. WIth Sony cameras, the Sony app store sells a software intervalometer called Timelapse, but hardware versions are also available for a reasonable price.

[StephanN]

Why would you NEED a ND filter in UV? The problem is usually that we never have enough light! But anyway, my suggestion would be to do what I did with the astronomy software in the Queen Anne's Lace UVIVF thread and just take lots of images using an intervalometer then average them using the astronomy software. On the Mac I use Long Exposure Stacker (which is available in the app store) but there are many others. WIth Sony cameras, the Sony app store sells a software intervalometer called Timelapse, but hardware versions are also available for a reasonable price.

 

 

Simple: The photos were all taken at f/16, and If I want to have less depth of field but still an exposure time of 30s (or more) to get that smooth water, then I need an ND-filter. You know, similar to taking portraits at f/1.2 in bright sunlight

 

But, nothing easier than taking my ND filter and try them out, I'll do that on the weekend.

[Andy Perrin]

OR you could take my suggestion and then you don't need an exposure time of 30 seconds.

[StephanN]

OR you could take my suggestion and then you don't need an exposure time of 30 seconds.

 

 

True, but like seeing the result immediately in the field and not back home on the PC

[Andy Perrin]

Assuming your ND works properly in UV and doesn't limit the bandpass too much...but I guess we'll see. You may not notice the difference in grayscale anyhow.

[Stefano]

If your ND filters are made of polycarbonate (like most 3D glasses polarizer lenses) then they may block UV. The polarizers in my 3D glasses I have at home block UV. If they are made of glass they may behave differently, but of course testing them is the easiest and simplest way of knowing the answer.

 

If reach is not important, as suggested by Bernard, then using a bad UV lens may do the job?

[JMC]

Thanks for the information on the filters you used Stephan. Great pictures - its rendering suits that subject really well.

 

I see there is a little blip in the IR region for that filter combination. If you have any UV photos of flowers, it would be interesting to see whether that small IR blip is causing you any problems with capturing the UV.

[StephanN]

OR you could take my suggestion and then you don't need an exposure time of 30 seconds.

 

 

Andy, please don't think that I'm dismissing your excellent suggestion out of hand. I know that with averaging one can reduce noise, or one can't do startrails with one single long exposure, and I am dimly aware that proper galaxy photos require hundreds or even thousands of photos. However, while it's fun waiting to see what StarStaX does to your 120 exposures, I think it's more fun to see the terrestial long exposures immediately afterwards

[StephanN]

Thanks for the information on the filters you used Stephan. Great pictures - its rendering suits that subject really well.

 

I see there is a little blip in the IR region for that filter combination. If you have any UV photos of flowers, it would be interesting to see whether that small IR blip is causing you any problems with capturing the UV.

 

 

Thanks.

 

Well, I've taken some UV photos of flowers, but for those I've used the Baader U filter

 

[Edit]Actually I did take some flower photos with the Maxmax-filter combination, but for the ones from my balcony (comparison UV, VIS, IR) I don't know what they are, and the ones from the Botanical Gardens, where I know what they are, I only took VIS and UV[/Edit]

[Andy Perrin]

Andy, please don't think that I'm dismissing your excellent suggestion out of hand. I know that with averaging one can reduce noise, or one can't do startrails with one single long exposure, and I am dimly aware that proper galaxy photos require hundreds or even thousands of photos. However, while it's fun waiting to see what StarStaX does to your 120 exposures, I think it's more fun to see the terrestial long exposures immediately afterwards

 

Yes, but YOU don't need hundreds or thousands of photos. You aren't trying to get rid of noise. Your purpose is just to keep your sensor from saturating. So you need whatever the maximum exposure time is for your settings multiplied by whatever gets you past 30 sec. So if your sensor starts to saturate at 10 sec, you should take 3 10-second photos. You will still get your instant feedback, since a 10 second exposure and a 30 sec aren't going to be all that different? Also, it occurs to me that with only a handful of photos you could combine them in Photoshop or Lightroom rather than an astronomy program.