Focus and UV filter

[robin28]

I am having all the usual difficulty photographing very small animals (spiders) in the wild with a hand held camera. I have two lenses, an 18-140 Nikkor zoom and an 85mm micro Nikkor. Both seem to get me within 150-200 mm of the subject where depth of field and camera / subject movement present the expected challenges.

One techie question: both lenses are protected by UV filters. Can the filters be affecting the automatic focus on my D5300 in these near-limiting situations?

Robin

[Manfred M]

Can the filters be affecting the automatic focus on my D5300 in these near-limiting situations?

Welcome to CiC, Robin(?). If you wouldn't mind adding your name and where you are from to your profile, this would be great. Just click the "My Profile" tab at the top of this page to do this. We are quite informal here at CiC, and go on a first-name basis.

I'm going to move this post to the equipment section, where you are more likely to see other members views too.

The answer to your question is quite easy; no. If you are not sure that this is the case, take off the filters and try to shoot without them to confirm... It won't hurt your lenses. I have several that cannot take a filter, so I can confirm that there is minimal risk to your lenses.

The issue is more likely to be something else with your setup as some of the autofocus modes tend to pick the wrong thing to focus on. If you are close to the near focus limit, you might actually be on the wrong side of it and this could explain your problem too.

[pnodrog]

I never use auto focus on close subjects. Usually I manually focus for the working distance. If I am not using a tripod (hand holding) I adjust the final focus by moving my stance either slightly closer or further away and then rely on a small aperture to produce an extended depth of field.

[DanK]

I really doubt that the filters have anything to do with it. AF is not very reliable in macro work, and I generally don't rely on it. Unless you have a focus point aimed right where you want it and that area happens to be high-contrast, it often won't work well. The DOF is extremely narrow, so there is no margin for focusing on the wrong thing. I do sometimes use AF to get close, but then I move the camera to achieve focus. I always have AF on the back button in doing macro work so that tripping the shutter doesn't activate AF and spoil the focus.

[Stagecoach]

Robin, I would suggest that if you are dealing with spiders at 'macro' magnifications you forget about using AF.

The reason for this is that it is most likely that any area that falls within the Auto Focus point (rectangle) although having good contrast will also include parts of the subject that are at differing distances from the sensor. When this is the case you have no control over exactly which camera to subject distance the AF system locks on to. In addition once the AF is locked the slightest physical movement of you/camera will affect the end result of the focus plane.

Try manually moving the camera whilst concentrating your eye on the exact spot you want in 'sharpest' focus and as soon as it appears sharp gently press that shutter the rest of the way.

This is not to say that AF can not work fine if there is both good contrast and the subject area within the focus detection rectangle is all on roughly the same plane as the camera sensor.

[robin28]

Thanks, all, it does not get any better! Spiders, like most wildlife, show little willingness to pose for their portraits. So I find myself addressing a moving target on a branch swaying in the wind from a stance halfway into a gorse bush on the side of a small hill. And the depth of field in normal sunlight covers a quarter of the animal, at best. I imagine this is quite usual in wildlife photography.

Focus stacking is out of the question unless a stage can be constructed and the subject persuaded to keep still (another subject).

The other approaches seem to involve much more and better lighting. The expensive way would be to use the Nikon Close-up Speedlight Commander Kit R1C1. Can someone who has used it please share some of the pros and cons?

Alternatively, I have seen that some people use home made arrangements with a lot of success. Presumably they do not work with the Nikon exposure control system? Do I need a supply of old fag packets and stubs of pencil? I have a couple of old Olympus flash units but how do I synchronise them? And how is the exposure calculation affected by an improvised diffuser?

Robin

[xpatUSA]

Alternatively, I have seen that some people use home made arrangements with a lot of success. Presumably they do not work with the Nikon exposure control system?

Not sure why that should be so. Would recommend spot metering for spiders and manual exposure control and, as has already been said, manual focus, preferably in magnified live view if your camera can do that.

Do I need a supply of old fag packets . . .

That is unlikely to be understood correctly, especially here in the USA. OZ, NZ or SA maybe.

[robin28]

Sorry, cigarette packets.

Maybe I have not understood how the exposure control system operates. Does it measure incoming light during the exposure and just close the shutter when it has enough? I thought it was more complex than that?

Robin

[xpatUSA]

Sorry, cigarette packets.

Maybe I have not understood how the exposure control system operates. Does it measure incoming light during the exposure and just close the shutter when it has enough? I thought it was more complex than that?

Robin

The automatic exposure function (AE) indeed measures the light - but before the act of exposure, not during it. In other words, it presets the exposure value before the button is pressed all the way down to complete the shot. There are some variations and complications of this simple statement and others may be along shortly to tell us what those are. The word "exposure", when used by itself, has several meanings in our hobby (how unusual) which can lead to confusion especially when the so-called "exposure triangle" gets mentioned

To my simple mind, 'exposure' is how much light is allowed to fall upon the sensor (aperture) and for how long (shutter speed) and it is measured in lux-seconds.

[DanK]

Focus stacking is out of the question unless a stage can be constructed and the subject persuaded to keep still (another subject).

The other approaches seem to involve much more and better lighting. The expensive way would be to use the Nikon Close-up Speedlight Commander Kit R1C1. Can someone who has used it please share some of the pros and cons?

Alternatively, I have seen that some people use home made arrangements with a lot of success. Presumably they do not work with the Nikon exposure control system? Do I need a supply of old fag packets and stubs of pencil? I have a couple of old Olympus flash units but how do I synchronise them? And how is the exposure calculation affected by an improvised diffuser?

Robin

For lighting, the most common approach among people I know is to use a highly diffused regular flash, held near the end of the lens. The brackets and diffusers are often DIY. Mine are. I will post a picture of my current one. To see how the diffuser is made, google "coke can diffuser" without the quotes. The diffusion surface can be be lots of things. Paper towel works well. My current one is two sheets of baking parchment paper. The bracket is a straight flash bracket that I drilled out to accommodate two mini ball heads. With this, my standard is 1/125, f/13 or so. The only drawback is weight and the balance point, which is moved forward. I use a monopod most of the time to stabilize it.

Even with good lighting, focusing in macro work with anything that moves is very tough, and adding flash won't make AF any better. That's why people who shoot a lot of macro generally don't rely on it. I still assume that most of my shots will not have accurate enough focus to use. I generally keep taking them for some time until the bug gets fed up and leaves.

[rpcrowe]

IMO, you greatly benefit from additional light when doing macro work. Dan illustrated a good system and my system, although slightly different from Dan's system, should provide pretty equivalent lighting; which is a diffused flash at a close distance from your subject...



However, I think that when "I find myself addressing a moving target on a branch swaying in the wind from a stance halfway into a gorse bush on the side of a small hill. And the depth of field in normal sunlight covers a quarter of the animal, at best." You are pretty well putting yourself in a difficult and possibly unworkable situation. There are just too many variables of motion in your system. 1. spider, 2. branch moving in the breeze, 3. extreme narrow DOF and finally 4. camera movement...

I would try to minimize these problems by adding extra light (if you are shooting from a distance, neither Dan's nor my setup would work well, and by shooting at the very highest ISO which will allow you a decent image with your camera...

[robin28]

... measures the light - but before the act of exposure, not during it. In other words, it presets the exposure value before the button is pressed all the way down ...

Brilliant! I have two old flash guns (Olympus Electronic Flash T20 and T32); the small one is currently directly on top of the camera with the other on a bracket fired by a photoelectric trigger.

But I see no way they can communicate with a Nikon D5300 to set exposure / aperture. How does it know how much light the flash will contribute?

Robin

[DanK]

Robin,

A few other thoughts.

First, I had a hunch that maybe we are missing the forest for the trees by focusing on details rather than a basic point.

Modern cameras are so smart that in many situations, if you set things in a reasonable way, it just works. E.g., put an E-TTL bounce flash on, set the camera for ISO 400, f/4, and 1/60, put the focus point on the person's eye, and everything just works: most of your shots will be reasonably focused and reasonably exposed.

Not so with macro, particularly macro with moving subjects. Macro demands a lot of manual work. This is why both Grahame and I wrote that we don't trust AF in macro work. It doesn't matter what lighting you add, it just isn't going to work much of the time. Id you are adding continuous light, it may help a bit, but flash doesn't help because the camera doesn't have time to focus using the illumination of the flash. That leaves manual focusing, usually by moving the camera, which--unless you are much steadier than I am--means discarding most shots. If you read what people post on macro forums, this is common.

As for flash: I know nada about Nikons, but in the Canon world, E-TTL flashes (including all of their current models) meter off the actual flash exposure. They don't change the aperture; they simply change the amount of flash on the basis of the amount of light getting to the sensor, given the aperture you have set. You may need to bump it up or down with flash exposure compensation in some settings, but for the most part, it just works. That's why I usually shoot bugs at 1/60, f/13. The flash metering system adjusts for the amount of exposure from the flash and ambient light.

Dan

[Stagecoach]

The other approaches seem to involve much more and better lighting. The expensive way would be to use the Nikon Close-up Speedlight Commander Kit R1C1. Can someone who has used it please share some of the pros and cons?

Robin

I have had the R1C1 kit for a number of years and am fortunate in that my cameras can use the on board pop up flash as a commander to trigger these without having to use a separate SU-800 commander unit. I'm not sure if your camera has the flash 'commander' function.

The units are expensive but also versatile in that they will easily allow you to position the SBR200 flash units anywhere within a 360 degree rotation to light your subject from any angle. This is especially useful when wanting to manoeuvre within foliage or obstacles. In addition different power levels can be used on each thus changing the light intensity ratio giving a more natural appearance to the lighting and eliminating single direction shadows.

Since purchasing these at the beginning of my journey into macro I have also experimented with many different designs of the 'coke can, cardboard, lash together' home made diffusers fitted on both camera and off camera flash units. The design of these and generally similar to what Dan has posted determine your accessibility in tight situations.

What I will say is results achieved with these home made designs can be just as good as I can achieve with the expensive R1C1 kit.

[robin28]

... everything just works ... Not so with macro ...

Yes, I had registered what you wrote earlier. I know I am going to have to get to grips with the host of compensation settings this camera provides. I just didn't spot anything in the manual about how the automatic systems work with more complex flash combinations. I suspect these two flash units are so old (certainly before E-TTL) there is no alternative to old fashioned pencil and paper.

It's time to call a halt to this. I need to go and read a lot about modern flash systems. Thank you, everyone, for all your help.

[xpatUSA]

... measures the light - but before the act of exposure, not during it. In other words, it presets the exposure value before the button is pressed all the way down ...

But I see no way [two old flash guns] can communicate with a Nikon D5300 to set exposure / aperture. How does [the Nikon D3500] know how much light the flash will contribute? Robin

I was not talking about flash photography. Good luck with your research on that subject.

[Dave Humphries]

Yes, I had registered what you wrote earlier. I know I am going to have to get to grips with the host of compensation settings this camera provides. I just didn't spot anything in the manual about how the automatic systems work with more complex flash combinations. I suspect these two flash units are so old (certainly before E-TTL) there is no alternative to old fashioned pencil and paper.

It's time to call a halt to this. I need to go and read a lot about modern flash systems. Thank you, everyone, for all your help.

Hi Robin,

If you're still here (hope so), I'd like to say that there is much good advice above.

However, I'm not sure you need to be so dependent upon the automatics working and learning how to drive them.

In macro work we usually want the biggest image of a tiny subject, that in turn means getting as close as the lens' minimum focus distance allows. So now we have effectively fixed the camera to subject distance and, assuming the flash is attached to the camera, the flash to subject distance too. So now my thinking goes that apart from variations of subject tone (e.g. black spider, white spider or somewhere in between) a lot of the exposure variables are now fixed and you'll soon get a feel, if you practice, for which manual settings work.

You may find this more productive and satisfying than doing too much home work and over reliance on automatics which may be fooled by circumstances that might be irrelevant.

However, we each have our own best way of working (and learning), so the choice is yours.

Welcome to the CiC forums from me, Dave