FX full-frame macro: some observations

I rarely use a full frame camera for macro shooting, probably because it offers 1.5x less effective magnification than my D300 with its DX or APS size sensor. This means its easier to fill the frame of a D300 with a subject when working a bit further away, which is good for active and easily spooked bugs like dragonflies.

The D300 is a good APS macro camera with a relatively bright 100% coverage viewfinder, which makes focus reasonably easy. With its performance in low light being very good, but still short of the full-frame camera, I tend to limit my ISO to 400 on almost all shots (a few very successful shots at ISO 800), which for photographing bugs, usually means using flash to get enough light.

For my recent couple of excursions with the full-frame D700 I chose the Carl Zeiss 100 F2 Macro Planar lens, as I was keen to use it for more bug shots and love its optical and mechanical qualities. With the D700 it gives a very different formula to the D300/Sigma 150mm combination.

The D700/ Zeiss combo of course restricts the working distance and magnification very notably, especially as the Zeiss "only" goes to 1:2, so you need stealth and more cooperative subjects if you get close. It tends to inspire more environmental portraits where the animal is a smaller part of the composition. Technically this combo gives greatly enhanced possibilities for working in natural light by using higher ISO values and the big bright viewfinder is a revelation for focus, as its easy to see detail very clearly. I had little trouble focusing at F4 for the demoiselle shot. Even the best APS cameras have viewfinders with the appearance of looking down a tunnel in comparison. As there is no multiplier for effective focal length on full frame, a lower shutter speed is acceptable, making the combo less prone to camera shake. As a result of these factors my "hit-rate" was much improved.

I love macro shooting and its interesting to try different combinations of equipment to add some variety to my style of shooting and hopefully to add a different character to at least some of the shots. Having less magnification but other advantages certainly made me more aware of trying to compose some shots with environmental elements as well as the subject, which can only be good for creativity.

I haven't tried flash yet on the D700 and Zeiss lens...I will report if and when I do!

Mating Damselflies, Macro Exposure and Flash

20100605-_DSC6693 Mating Damselflies
Originally uploaded by ClifB

As usual with photography getting the shot right is about compromising on one factor to gain another and that is certainly true of macro exposures. This post is a brief exploration on my experiences of juggling shutter speed, aperture value, ISO and flash type and level.

Bear in mind I am a Nikon user and some of the detail may be different on other camera systems, though the principles will be the same. I always use manual exposure mode for macro and close-up shooting with flash so I know what shutter speed and aperture are locked into the camera, as any unexpected alteration of them can seriously compromise the shot.

I tend to find that when shooting at 1:1 and greater magnification then I will use TTL flash which meters directly off the subject and lights it, taking no account of the ambient background exposure. This makes sense as the animal will often fill a large area of the frame. I am generally not a fan of fully dark backgrounds caused by massive underexposure of the ambient conditions, so tend to select an aperture and shutter speed combo that allows some ambient light to creep in and give a colour to the background, or I make sure it gets some of the light from the flash. I tend to dial in a varying amount of negative flash compensation to make the light more subtle and reduce harsh reflections. Usually -0.7 to -1.

When shooting bigger animals at considerably less than 1:1, or including more of the animal's environment, clearly the ambient light has a much greater effect on exposure, which is a good thing as it adds to the environmental feel of the image. I still like to add some flash in many cases to fill shadows and to use its very short duration to help to freeze camera or subject motion. In this case I find that TTL flash can often overexpose and completely burn out the subject. Therefore for this type of environmental image I tend to select TTL-BL, which is balanced fill flash. This meters the whole frame, including the subject and background and uses the flash to balance the illumination of the subject with the background and therefore the ambient light conditions.

Being limited to a flash sync speed of 1/250th sec influences choice of aperture to achieve an ideal exposure value between 0EV and approximately -1EV relative to ambient light. Clearly if ambient light is very bright you cannot raise the shutter speed to reduce EV, you have to close down the aperture a bit and select a low ISO value instead. If ambient light is weak and you struggle to avoid serious underexposure you can drop the shutter speed a bit to say 1/200th, open the aperture up and raise the ISO. Always bear in mind that opening the aperture will reduce depth of field and raising ISO will reduce image quality...as always its a trade off to get the exposure you want, so alter things within a range you know works.

This shot of the mating damselflies is a good example of the issues and techniques discussed above. I wanted to use a balance of ambient and flash light while retaining a light, colourful and out of focus background. I also needed an aperture that would enable me to get the eyes of both animals in focus...very tricky owing to the small depth of field at close distances. The animals cover a relatively small area of the frame compared to a real close-in image, so it is more of an environmental shot.

As there was a slight but intermittent breeze and I was using a 150mm lens (225mm equiv. on APS sensor camera) I wanted to use the max shutter speed available of 1/250th. I set an aperture of F9 to give me enough DOF, but this combination resulted in a rather low exposure value relative to the ambient light. To get around this I selected ISO 400, which is usually the max I will go to for macro where detail is essential. I therefore gained a stop of exposure without altering shutter or aperture settings. Another benefit of raising ISO is that the flash output is reduced. This makes recycling faster to the next shot and makes the light more subtle, with less chance of nasty reflections on shiny insect cuticles and eyes.

Its all about practising with your kit and finding what works for you. I guess the holy grail of macro shots are those where it isn't obvious that you used flash as they have nice balanced lighting, no harsh shadows and no harsh highlights or reflections. Using a balance of ambient light and flash is one way in which this can be achieved with care.

Chettle House gardens

20100531-DSC_2431 Chettle House gardens
Originally uploaded by ClifB

I found another reason to love the D80 and the little Nikon 35mm F1.8 prime at the weekend.

I recently had a car smash and have a lot of chest and soft tissue strain injuries. I simply can't hold a D700 and F2.8 zoom at the moment. I have been trying to get out for a walk for a few hours here and there to aid getting back to fitness (and avoid boredom insanity!) and found I can manage the lightweight D80 and this little prime as long as I don't reach or have to get into awkward positions....yay!

So as well as a walk-around, travel and low light lens it is now a lens for one with compromised physical ability!

I actually think the sharpness and bokeh is top grade for a lens of this price and the AF is spot-on, even at wide apertures. If you are a DX shooter with a kit zoom, this lens will add a new dimension in creativity with its image quality, depth of field control and low-light capability.

I consider it to be one of Nikon's most important recent lenses because it brings such important creative qualities to the budget-conscious photographer at a sensible price, when so much new kit is priced into the stratosphere and wholly inaccessible.

The 35mm F1.8G DX...don't leave home without it!