Full Moon Tonight

Handheld shot of the moon, AF-S NIKKOR 70-300mm f/4.5-5.6 IF-ED.

Taken just moments ago. It seems to be a good test of any telephoto lens to attempt this. This was taken with the Nikon AF-S NIKKOR 70-300mm f/4.5-5.6G IF-ED at 1/400s, f/8, ISO 200, handheld. At the long end, it’s 450mm on the D90. Thank goodness for VR, not that shooting at 1/400 sec. is that challenging. The moon is so bright that you can shoot this fast with a low ISO and relatively small aperture to capture all the detail.

Here’s a tight crop...

Full Moon taken with Nikon D90 with Nikon 70-300mm f/3.5-5.6 Zoom
1/400s, f/8, ISO 200, 450mm

I didn’t think it fair to post this as the actual image. It’s been cropped, resampled to the original pixel dimensions, and sharpened. It doesn’t make a bad photo.

This is a true test of the sensor’s resolving capability. There would be more detail if this were captured on film, but the focal length would have been 300mm, instead of 450mm, so it might be a wash. If I captured this with an FX camera, say the D700, the reduced focal length might also have killed the sensor resolution, which is the same as the D90 in DX format.

Here’s a photo of an almost full moon taken back in December 2009 with My Nikon Coolpix P5100 and Opteka 3.3x teleconverter, and enlarged and sharpened by the same amount:

Almost Full Moon Taken with Nikon Coolpix P5100 with Opteka 3.3x Teleconverter
1/100s, f/5.3, ISO 64, 406mm

Obviously the D90 image is superior, but I’m pretty impressed by the P5100, especially considering its tiny sensor (by comparison to the D90) and reduced focal length.

Since both of these images were not taken under the same circumstances, if it’s clear tonight I think I’ll attempt to take another photo with the P5100 at ISO 200.

Macro on the Cheap, Part II

Reversing a wide-angle lens with a reverse mount adapter is a pretty neat and inexpensive way of creating a manual focus, manual exposure macro setup without buying more lenses. The flip side to that is creating an auto-focus, auto exposure macro setup which is more convenient, albeit at the expense of speed.

Typically this is done by reversing a 50mm lens and attaching it to an existing auto exposure and/or auto focus lens. As with mounting the lens directly to the camera body in reverse, the wider the angle, the greater the magnification. However, this technique is prone to vignetting which may increase as the angle gets wider.

What we need to do this is known as a reverse coupler, a simple device with two male filter threads which allows you to attach two lenses front to front. The reversed lens behaves just like a closeup lens that screws onto your filter threads. A multi-element, multi-coated, high-diopter, closeup lens.

It works like this; if you add a magnifying (convex) lens in front of your main lens, it shortens the minimum focusing distance so that in order to achieve focus, you need to move closer to the subject. When you do, the subject is magnified in the process. Since a normal lens gathers light from the scene and reduces it to fit onto the camera’s film frame (or sensor) flipping it around has the opposite effect…it becomes a magnifier!

To figure out the diopter value, divide 1000 by the lens’ focal length. So, a 50mm lens would have a diopter of 20. Compare that to a stack of three typical closeup lenses which would give you a total diopter of 8, and degrade image quality with significant chromatic and spherical aberration.

Since this technique often produces vignetting effects, you might want to test your intended “diopter” lens first by “freelensing”; hold the reversed lens up to your main lens with the aperture wide open to see if the image circle is reduced significantly. Setting the “diopter” lens to its shortest focus distance will enlarge the image circle, but reduce the working distance. Also, make sure all filters are removed from the facing filter threads to reduce the lens-to-lens distance as much as possible.

The Nikon BR-6 Auto Diaphragm Ring helps here as well. Even though you won’t be using the aperture of the “diopter” lens, you can use the BR-6 to set it to its widest position, and add a filter to protect the rear element.

Holga, The Lomography “System” Camera

Here’s my growing Holga outfit so far...

Clockwise from center: Holga 120FN, 6x4.5cm mask, 6x6cm mask, 35mm mask,
35mm back, filter adapter, cable release adapter, 46-52mm step-up ring

Being the camera geek that I am, I couldn’t resist putting together a system for the Holga, just as I did for the Nikon Coolpix P5100. With this setup, I can shoot two different formats of 120 film, and two different formats of 35mm film.

Not pictured here is the additional 6x6cm mask that I plan on modifying to create a 35mm panoramic sprocket hole adapter. I figure, if I’m going to load this thing with 35mm film, it should be to achieve a unique effect. Otherwise, I could just use my newly acquired Lavec LT-002.

The 46-52mm step-up ring is a handy way to add filters to the Holga. Although there are no filter threads per se on the Holga, the rim around the periphery of the lens is just the right size to allow a 46mm filter to be threaded on. You simply line up the filter as evenly as possible, apply a little pressure, and rotate about one-eighth of a turn. The filter will be firmly attached. Don’t try to thread it on all the way however, as this will likely break the rim off the lens. Over time, the rim will wear and you’ll be able to thread it on a little deeper, so the connection will just get better and better.

Taking this one step further, the 46-52mm step-up ring will allow me to use all my existing 52mm and 67mm filters, not to mention my Cokin filters.

One solid reason for the ability to use filters with the Holga is to employ neutral density filters. This way, you can load the camera with fast film for low-light situations, and use the neutral density filter to control exposure under brighter conditions.

The Holga filter adapter is a handy way to not only use the available Holga filters, but to make your own, which is one of the things that originally drew me to the Cokin filter system. Find some clear film from product packaging, trim it to a rectangle 1-15/16" x 2-1/4", and voilà! Instant filter base. Scratch it, sand it, mask out the center, color it with marker, anything you want.

I’m also considering the Holga .5x wide-angle converter lens. Although 60mm is nice and wide for 120 film, and should work well with the 35mm panoramic format, it’s a bit long for the straight 35mm adapter. I don’t know though; it’s going to set me back a whole $14.95.

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You can learn more about modifying your Holga at Holgamods.