DavidKennard

DavidKennard

Lives in United Kingdom Market Harborough, United Kingdom
Joined on Nov 15, 2009
About me:

I enjoy a wide range of photography styles, however I am particularly interested in macro and close-up photography of flora and invertebrates. While macro photography focuses on the very small, on the other hand I also enjoy 360° panoramic photography, capturing all of the scene around me. You can find my panoramas on 360vrs.com.

Another aspect of photography I have taken up recently is multispectral photography, photographing in visible light, ultraviolet, and infrared. I've been focusing on flowers, some of which have hidden patterns only visible in ultraviolet light. Bees and other insects can see these patterns, and it is believed the UV markings help them hone in on the centre of the flower where the nectar and pollen are located. You can find these images on my Vis UV IR Flower photos blog: http://vis-uv-ir-flower-photos.blogspot.com/

Comments

Total: 160, showing: 1 – 20
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In reply to:

DGrinb: It's been discussed so many times and still people don't get that f1.4 on MFT is not f2.8 on FF.

P.S. Kudos to the OM for keeping this going!!

So 20/1.4 != 40/2.8?

Link | Posted on Nov 4, 2021 at 20:21 UTC
In reply to:

torakawa: I'm sad to see DPR comment section now infested by brand fanboys and trolls. I used to enjoy reading insightful and intelligent comments but it's becoming just another rumor website. I would advocate for more heavy handed moderation by the staff, but short of that, would DPR consider implementing blocking functions?

I don't remember it ever being any different. You say it's "now infested by brand fanboys and trolls", when was the last time you visited the site? Or maybe previously you've just visited the non-brand specific articles, which don't attract the fanboys and trolls so much.

Link | Posted on Oct 18, 2021 at 20:04 UTC
In reply to:

photomxp0: Forensic digital cameras are typically full spectrum. It is unclear why Fujifilm has made this IR and visible spectrum only, rather than removing the UV cut sensor filter as well.

I don't think Fuji sells any Quartz lenses at all, yet they've made UVIR camera models before. You're right that there is a much smaller selection of UV suitable lenses for MF. Though I would think many enlarging lenses that cover the image circle would be suitable, and there may be some suitable FF lenses that have a large enough image circle.

Link | Posted on Dec 3, 2020 at 08:15 UTC
In reply to:

CanonKen: Do we have the real answer for why it is restricted? Is it because of perv use (if it would even apply in this case), or is there something 'bad' you can do with it?

I had one of their previous cameras and I'm sure the agreement said you weren't allowed to use it to help make bombs. You were also prohibited from selling the camera on. It might be some Japanese specific restriction as conversion services (based outside Japan) don't require you to sign anything like that.

Link | Posted on Nov 26, 2020 at 21:09 UTC
In reply to:

photomxp0: Forensic digital cameras are typically full spectrum. It is unclear why Fujifilm has made this IR and visible spectrum only, rather than removing the UV cut sensor filter as well.

I wonder if they have kept in the UV cut filter, or they just thought that there is so little demand for UV imaging they didn't mention it also works with UV. I can't find any reference to the wavelength range the sensor works with.
Previous Fuji cameras have been UVIR, so it seems a bit strange that this one wouldn't be also.

Link | Posted on Nov 26, 2020 at 21:04 UTC
In reply to:

entoman: First we had ASA and DIN sensitivity ratings, then we got ISO. If numbers rise much higher, we're gonna need to come up with yet another system...

I use M58 adapters, but I had to make them myself. I don't have any M58 lenses but it is a useful mount size for using a helical with projector lenses (M42 is too narrow). Interesting to hear it is used as a native mount.

Link | Posted on Nov 6, 2020 at 19:35 UTC
In reply to:

RegisS: It looks like this lens works on a lab bench with the subject illuminated by a specific wavelength of light. To use this lens in natural light, it would need a narrowband optical filter to block all but the wavelength the lens is designed for. That's a lot of light loss. There may be machine vision robotic uses for this tech, but it won't be much use as a cellphone camera lens.

I think most existing fisheyes are fine for NIR photography, a UV capable fisheye would be great though, so long as it doesn't cost too much.

Link | Posted on Sep 22, 2020 at 07:40 UTC
In reply to:

entoman: Regardless of whether I used LR, ON1, Photos or any other editing/DAM application, there's absolutely no way that I'd risk having the "cloud" (i.e. a bunch of easily hackable servers) as my primary storage.

Infinitely more secure to have duplicate sets on a pair of cheap portable drives, and to keep one of them off-site as security against fire or house burglary.

But I guess it makes some sort of sense for some people, to store a small selection of images on the cloud, in order to share them more easily.

@tkbslc The 'cloud' may be more difficult to hack than your desktop, but it's a much more likely target for hackers (and so more likely to get hacked) than your desktop.

Link | Posted on Jul 12, 2020 at 20:59 UTC
In reply to:

landscaper1: I have a feeling that it's just as easy to equip each lens with it's own step-up filter(s) to whatever the largest filter size that would fit at least one of the lenses. Then leave those on all the time.

Then there's the same idea taken one step further where the filter is fitted with a metal ring designed to mate to a magnetic adapter on each lens, which makes the process of changing filters much faster than screwing and unscrewing threaded filters.

I think it depends on the sizes of your lenses, with smaller lenses using a large step-up ring can make it more difficult to get the lens out of / into your bag, plus makes it take up more room than it would otherwise.

You also have the problem of lens hoods no longer fitting, but that problem still exists with this adapter. This can be worked around with a collapsible rubber lens hood, but it's not ideal.

Link | Posted on Jun 30, 2020 at 21:14 UTC
In reply to:

Toselli: More than a new A7S I'd like to see an A7M (monochrome). Or really whatever camera in monochrome!

I'd be interested in an A7MFS (Monochrome full spectrum), but that would be even more niche than a hot mirrored monochrome. I don't think there is enough demand for monochrome cameras for them to be produced in quantities that allow for reasonable pricing e.g. check the prices of monochrome cameras from Leica and Phase One.

Link | Posted on Jun 29, 2020 at 15:12 UTC

Anyone use a UVIR cut (Hot Mirror) clip filter on a full spectrum modified mirrorless camera? Just wondering how well they work for making a converted camera work like a standard camera?

Link | Posted on Jun 18, 2020 at 20:41 UTC as 28th comment | 1 reply
In reply to:

lancasterjohn: I think UV filters with digital cameras can be replaced with what are called protector filters. I don't want to clean the from of my lens for fear of scratching it, but I will happily clean a filter.

They're basically the same thing. A lot of cheap UV filters don't even block UV.

Link | Posted on Jun 13, 2020 at 10:58 UTC
In reply to:

khunpapa: "there was no official way to adapt it to a modern lens mount"

There's a lot of DIY in the net. The best is making the 'body' from the PVC plumbing tube. Glue one end to the 'universal' m42 mount (easier to find the mount adapter for your camera). Another end to the lens. That's all. Helix focusing tube is the good 'investment' too.

Some of the DIY 'guru' in my town even glue this PVC mount to the lens.

RAF camera make a variety of projector lens adapters - no need to canabalise an existing lens or permanently modify the projector lens.

Link | Posted on Apr 2, 2019 at 17:35 UTC
In reply to:

Giulio Severini: The saddest thing about it is that you need Chrome to view it in 4K.

Works fine in 4K in Firefox for me? (The first video that is, the Troll promo seems to be 1080 even in Chrome).

Link | Posted on Mar 22, 2019 at 20:40 UTC
In reply to:

jjl: I'll go against popular sentiment on this one.

Copyright is there to prevent copying of your images. People using these images for machine learning don't need to copy your images. If you've uploaded your images to their server, you've already done the copying. All they are doing is looking at the images, creating their own tag data, and then using a combination of the image and the tag data to generate an algorithm. What was unique about that image is completely lost in the process. There's no way to re-extract the image's data from the result.

To me, the people who do this are making a derivative work, and that should be allowed.

If you remove your images from the server, they'll no longer be available - which is how it should be. If you look at these creative commons data sets, there are missing images, due to this reason. They have to constantly refresh it.

Also - not that it matters for legal reasons - they don't need quality images for this, just quantity.

@Olifaunt There are various CC licences, some allow for non-commercial usage only, others do allow for commercial usage. However, if IBM paid Flickr anything is irrelevant as the photos were licensed by the individuals to IBM (or anyone else wanting to use them), not by Flickr.

Link | Posted on Mar 20, 2019 at 22:02 UTC
In reply to:

jjl: I'll go against popular sentiment on this one.

Copyright is there to prevent copying of your images. People using these images for machine learning don't need to copy your images. If you've uploaded your images to their server, you've already done the copying. All they are doing is looking at the images, creating their own tag data, and then using a combination of the image and the tag data to generate an algorithm. What was unique about that image is completely lost in the process. There's no way to re-extract the image's data from the result.

To me, the people who do this are making a derivative work, and that should be allowed.

If you remove your images from the server, they'll no longer be available - which is how it should be. If you look at these creative commons data sets, there are missing images, due to this reason. They have to constantly refresh it.

Also - not that it matters for legal reasons - they don't need quality images for this, just quantity.

Just to be clear, once you've granted a creative commons licence to someone, you can't rescind it. This applies to all image licences, unless the terms of the licence specify otherwise, of course. A licence would be completely pointless if it could be rescinded at any time.
So if you previously applied a CC licence to an image, which IBM then obtained under that licence, if you delete the image from flickr or change the licensing terms, that only affects anyone that wants to use the image and hasn't already obtained the image under the previous licence. So IBM can still use your image they previously licenced even if you delete it completely from Flickr.

Why people would licence their image out and then get annoyed when someone uses the image under that licence is beyond me.

Link | Posted on Mar 16, 2019 at 08:15 UTC
On article CP+ 2019: Hands-on with Tokina Opera 16-28mm F2.8 FF (55 comments in total)

How much would it have cost them to stick a gel filter holder on the rear? Seems an odd omission. Likewise the fixed hood will likely make using large filters on the front very difficult. I can't imagine it would have cost much more to make the hood removable.
I guess for Canon R mount users at least they can put a filter in the adapter.

Link | Posted on Mar 3, 2019 at 17:10 UTC as 10th comment | 2 replies

So could this be used as a free 'cloud' backup service? Just upload everything there, and you'll only have to pay if you need to recover files from it?

Link | Posted on Feb 27, 2019 at 07:47 UTC as 1st comment | 1 reply
In reply to:

endofoto: We are all discussing about mirrorless, yet best innovative lenses are still produced for DSLR. Lens companies will decide whether DSLR will be exterminated or not. At this price it will sell and DSLR will survive.

You do realise DSLR lenses can be used on mirrorless cameras? It could be argued that lenses such as this one are actually more useful on mirrorless than they are on SLR bodies (due to being able to use the lens with mount adapters that allow tilt or shift or filters).

Link | Posted on Feb 23, 2019 at 08:27 UTC
In reply to:

jim seekers: So these are cheaper in the United Kingdom and more expensive in the United States, at last.

@moTmeN I presume these are made by Cosina in Japan, not in Europe, so there would be custom fees. I could be wrong?

Link | Posted on Jan 31, 2019 at 19:26 UTC
Total: 160, showing: 1 – 20
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