A camera operator will most often use the depth of focus formula when they are inserting or removing gels or UV filters from their camera. Gels and filters are often placed between the lens and a camera’s image sensor, and so adding or subtracting them changes the distance between the plate and the lens. Most consumer cameras have built in filters, or filters that are placed on the outside of the lens, so these calculations usually only come into play for higher-end or older cameras.

Thanks @Andrea B. for this test. My favorite turned out to be the Baader I own. The other ones really surprised me though, didn't call any of them. As a side note I have my S8612 now to test with some Chinese zwb 1 and 2's I have, and really liking what I got with the  ZWB1 2mm?/S8612 2mm. I know that ZWB1 filter might not be accurate, but pretty sure it lets less from the upper range through as there's way less purple than the Baader. I need to get out after cleaning both my Nikkor 80's to find the best one out of them.

Faculty360

However these lines are drawn in a gradual transition range where human vision tapers of. That change is not an abrupt change.

Hoya 360login

Very true, I may have been starting to get obsessed with perfect lens condition with the tear down and cleaning of my Nikkor 80's and wanting only below 400nm, when the Baader  brings the sharpest image, and is the fastest filter I've used. Less testing, more enjoying taking shots.

HoyaHousing

HOWEVER, I do share the feeling with others that this current AndreaU Mk-II is a bit slow. And that the description of the AU-II on UVR Optics is not accurate, given the results we've just seen here. I just don't think the AU-II I used in these examples is quite like the one which I tested in 2016.

Georgetown Canvas Login

A visual medium requires visual methods. Master the art of visual storytelling with our FREE video series on directing and filmmaking techniques.

The AU2 site talks about really robust blocking above 400nm. They say this helps when making long exposures on low UV or even rainy days! Is there any truth in this?

I've always tried to distinguish between UV artistic and UV documentary efforts. All the filters and stacks which we discuss and use here on UVP are giving you a reflected UV photo. There might be a greater or lesser degree of "contamination" with bits of violet or green or low IR from a given filter or stack, but the only place where purity of wavelength is a serious requirement would be in a scientific lab situation. So we should enjoy all the filters we use knowing that we have seen part-way into the Invisible realm. So cool!!

The AU2 site talks about really robust blocking above 400nm. They say this helps when making long exposures on low UV or even rainy days! Is there any truth in this?

So far, it might seem like depth of focus is pretty much the same as depth of field. What is the difference between depth of field and depth of focus? Isn’t depth of field also about the range of acceptable focus in an image?

Gu360

For those aforementioned reasons, depth of focus is the more obscure cousin of depth of field, and most casual photographers and cinematographers can get by without ever understanding what it is. But for people who are serious about photography or cinematography and are dealing with high-end cameras, it’s a key concept to know.

I think the statement about rainy days is about the SEU-filters that takes advantage of the sensor's higher sensitivity close to 400nm.

If the images with a given filter or filter stack can deliver a pitch black UV-signature, and the stack can give images with normal UV-yellow flowers I see it as an OK UV-image.

I did not see a very big exposure time improvement with my SEU-filter, But it gives an interesting tonality, especially with flowers that have bluish false colours.

Hoyauniversity login

The image sensor in your camera is a plate that takes in light waves and translates them into the image you’re capturing. The image sensor is located behind a camera’s lens, the optical device which focuses the light from the scene onto the sensor. It’s the distance between these two camera components with which depth of focus is concerned.

Understanding this bit of terminology requires understanding some of the nitty-gritty technical aspects of your camera. It may seem like a complicated idea, but it’s key to making sure that your image is in focus.

Depth of focus is a term that is often forgotten until it becomes a problem; cinematographers might drive themselves crazy cleaning filters and adjusting depth of field settings, not realizing that their image sensor is outside the range of focus. So while this concept might not be front of mind when you walk onto set, it’s a good piece of knowledge to keep in your back pocket.

There are few terms in cinematography and photography more misunderstood than depth of focus. The term is often used interchangeably with depth of field, but the two ideas actually have two completely separate meanings. Depth of focus is critical to understand if you want to have a crisp image and a firm grasp on your camera operating skills. So what is depth of focus? And how is it different from depth of field?

@Andrea B. 3a definitely looks better with your editing. But, it takes a lot of adjustment to get there. If I already owned it, I would do the extra work. Don't see an advantage now. The Hoya U 360/ Schott S8612 has better color out of the camera, isn't dichroic, and is brighter than the AU2. If your AU2 is representive of current stock, the filter doesn't meet their claims of being brighter than the Baader U.

The wavelengths at 400nm and even 380nm, at some places, are used scientifically to define where UV starts and VIS begins. That is undeniable.

Now, it’s a good time to brush up on its more famous counterpart: depth of field. In this article we tell you everything you need to know about camera focus and creating compelling images using DOF.

Blocking further into VIS, and especially into NIR is a completely different thing as bad blocking here can give contamination.

The AU2 is AFAIK a glued ionic stack of some kind recommended as a better alternative for wide angle lenses as it is not dichroic.

@Andy Perrinfor preset LUT's, I use Affinity photo and it makes it really easy to make your own for any given color scene you encounter with different stacks/conditions. I'm sure the other editors do it too.

Georgetown GMS

We’re in a golden age of TV writing and development. More and more people are flocking to the small screen to find daily entertainment. So how can you break put from the pack and get your idea onto the small screen? We’re here to help.

It could be compared with some geographic state or nation borders that was defined using a ruler. Often the landscape on both sides is quite similar.

GU360 app

This isn’t often a desired effect, and if it is, you can usually have your frame be entirely out of focus by adjusting your lens’ focus ring or depth of field rather than moving your image sensor.

I might not have made it clear that there were the same number of "steps" taken in Photo Ninja to convert all 4 of the UV-pass examples. The only difference between the initial conversion of the initial example of the 3A/AndreaU Mk-II and the second example was a change in one existing step! In the first conversion I set the PN saturation slider to Plain/60. In the second conversion I set the PN saturation slider to Plain/100. I don't want to give the impression that any of the conversions I presented are necessarily optimal and/or complete should one want to produce a finished product suitable for printing and framing. We always give printable files a bit more spit & polish, yes?

Depth of focus refers to the space between the lens and the image sensor where the image being filmed will appear in focus to the human eye. If an image sensor is too close or too far from the lens, it is outside of the depth of focus and the photograph or footage will look blurry.

There’s a reason most amateur photographers and cinematographers know what depth of field is but might not know about depth of focus. Depth of field is often utilized to serve an artistic purpose — a shallow depth of field directs our attention to a very specific area in the frame; a deep depth of field allows for multiple subjects to be in focus at various distances from the lens.

One of the reasons is that I take pictures with many different filters and filter stacks, of the same motif,  to explore reflectance variations for different wavelengths in more detail.

The key difference between depth of focus and depth of field is that the former refers to the range of focus behind the camera lens. Depth of field refers to the range of focus in front of the camera lens. Here's a diagram to help put these concepts into perspective.

In this depth of focus formula, t is the depth of focus, N is the lens f-number, c is the circle of confusion, v is the image distance, and f is the focal length of the lens.

Depth of focus, meanwhile, is rarely altered in service of a creative choice. If your image sensor is outside the acceptable range of focus, your whole image will be blurry, not just certain objects within it.

@Andrea B.thanks for the clarification. So the AU2 doesn't require more work - good to know. Losing one of its main advantages - speed, it is tough to find a reason to pick it over the others. One other thing that comes to mind is a single filter that is thin and less likely to vignette on wide angle lenses. Guess some people might consider less false color a plus.

A general remark about reflected UV file conversions:  Hey, if I have to spend more than 2 minutes on the conversion part, then forget it! The core work of UV file conversion lies in getting a good white balance made* and then stored as a preset. After that it is just a few clicks on any file for which that prestored WB is usable.