LookCloser Posted April 12, 2021 Share Posted April 12, 2021 Hi All,I thought I’d make a start with my UV image posts here rather than in the botanicals section so I can make sure my shots and editing are up to standard. I am happy to receive constructive criticism.I am still waiting on my replacement full-spectrum modified so in the meantime I have just done a long exposure with an unconverted camera and the Kolarivision UV bandpass. Not ideal, but at least I do have a result.Subject: Pilostyles hamiltonii. The flowers do not open very wide, they look like buds but many of the flowers are open. A very unusual endoparasitic species sometimes called a “stemsucker”. The stem belongs to a different species (Daviesia) to the flowers.Details:Unconverted Olympus EM1MkII on a tripodEnna Munchen 35mm Lithagon f2.8Kolarivision UV bandpassDirect sunlight without additional illuminationf5.6, 3.2sec, ISO200 Link to comment
Andrea B. Posted April 15, 2021 Share Posted April 15, 2021 Hi - This is a good set of images for Pilostyles hamiltonii.And what an interesting thing this is. I have never heard of a "stemsucker" before seeing this!Thank you for showing this to us. The only thing I am not sure about is your white balance in the UV photo. Can you tell me how you made the WB?I would expect quite a lot less blue overall. Link to comment
Andrea B. Posted April 15, 2021 Share Posted April 15, 2021 P.S. I'll be looking forward to seeing this included in the botanicals section. Link to comment
Stefano Posted April 15, 2021 Share Posted April 15, 2021 The image looks infrared-ish to me, but maybe I am wrong. Link to comment
Andy Perrin Posted April 15, 2021 Share Posted April 15, 2021 Without additional blocking and with an unconverted camera, this may be mostly IR? I think some Kolari filters have had a substantial IR leak? If I remember right they replaced a leaky one for someone on the forum? Link to comment
Andrea B. Posted April 15, 2021 Share Posted April 15, 2021 It is difficult to know if there is some IR leak without knowing what the background plant is. There is a sufficient amount of dark areas in the photo for it to be UV. The stem is dark. The tips of the background plant are dark. But let's wait to hear from LookCloser. Link to comment
LookCloser Posted April 18, 2021 Author Share Posted April 18, 2021 Thanks for the comments Andrea, Stefano and Andy, I will say that taking this image was a spur of he moment decision so I was not completely appropriately set up for the task. In answer to your question Andrea, I took a white balance from a sheet of white styrene (plasticard) under the same natural light that I took the image. It may help that I also took an image using the white balance from vis spectrum image, but through the UV bandpass filter. I will attach that photo in the hope that it will help diagnose any issues with IR leaks. Obviously shooting through the stock hot mirror is part of the issue and will be remedied.If there is an IR leak, is the appropriate course of action to send the leaky filter back to the manufacturer or is a degree of IR leak acceptable and the solution is just to stack an IR cut filter? Link to comment
Andy Perrin Posted April 18, 2021 Share Posted April 18, 2021 Honestly you should stack an IR cut filter first if you are using an unconverted camera. It’s seems unreasonable to expect Kolari to make such a strong UV filter that it would work under those non-optimal conditions. If it still leaks after you test with a converted camera, give Kolari a call. Can you photograph a dandelion for us? That makes it much easier to tell if there is a leak since we know how they should appear. Link to comment
ulf Posted April 18, 2021 Share Posted April 18, 2021 The image looks infrared-ish to me, but maybe I am wrong.That is also my impression. Link to comment
nfoto Posted April 19, 2021 Share Posted April 19, 2021 I concur. This is largely an IR image. Link to comment
LookCloser Posted April 19, 2021 Author Share Posted April 19, 2021 Thanks everyone for your input on my first attempt. Sounds like I need to get my gear in order a bit more. I'll have a look through the stickies for a good IR cut filter. Then it will be a matter of waiting on that full spectrum conversion. Hopefully them I'll get some good UV images. Link to comment
Andy Perrin Posted April 19, 2021 Share Posted April 19, 2021 LookCloser, S8612 2mm is a great IR cut. It’s one of the most useful pieces of gear you can own for this hobby, even if you end up with a dichroic filter for UV eventually, it’s still useful for testing IR leakage. Link to comment
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