Glass I

Many things I have obtained, in the horrific financially-draining hobby of photography. This is part 2. (Click here for Part 1.)

Union 55mm +2 close up filter

I got this because it was cheap and lousy. Yes, I intentionally bought it for the chromatic aberration and softness it would give me.

A +2 close up filter changes your lens focus point from infinity to 50cm close. The math is 1000mm/diopter rating = focus point, so +1 = 1000/1 = 1000mm = 100cm; +2 = 50cm; +4 = 25cm; +10 = 10cm; +25 = 4cm.

Why would anyone buy a +2 instead of a +4?

So I could focus further away when the lens was on, and not have the insect I was shooting sense me so soon.

Hoya 55mm +4 close up filter

I got this as a more premium unit, at RM40. Stacked with the +2 it became effectively a +6.


When the +6 is used with my Minolta 50mm F1.4 (pre-RS) lens at F2.8, it enlarges the out-of-focus circles even more. The scratched texture you see is from a trashed 55mm UV filter, superglued to a 52mm UV filter ring. (My 50mm F1.4 had a 49mm filter thread size, with a 49-52mm step-up ring, so I had to use the superglued filters to reverse mount the close-up filters.)


At maximum out-of-focus-ness.


50mm at F6.3. This might give you a hint as to where this is.

Yes, close-up filters have the same effect whichever side you look through; it still has a positive enlargement.


Sony 18-70mm F3.5-5.6 lens at 70mm, F11, ISO100, 1/125 with flash on. Note the cheapo donut bokeh.


Minolta 70-210mm F4 beercan lens at 210mm, F32, ISO100, 1/125 with flash on, and +2 and +4 filters stacked on. I love the colorful distortion near the edges!


24/14mm = 1.71x magnification! Same exposure settings as previous picture.


At 210mm F4 with +6, the whites blur and bleed all over.


At 210mm F16, the effect is controlled and so much prettier.

Pro Tama 58mm close up/58mm 0.45x wide angle/fish eye set


From bottom to top: Minolta 50mm F1.4 lens, 49-52mm step-up ring, Hoya 52mm UV filter, 52-55mm step-up ring, 55-58mm step-up ring, Pro Tama 58mm macro, Pro Tama 58mm fisheye (which has a 67mm filter thread. Phew!)


The Octagon 55mm 0.45x wide angle converter, on my Vivitar 24mm F2.0 lens on my Olympus OM-2000 film SLR.

I got this instead of the Octagon 55mm 0.45x wide angle converter (also sold at Ampang Park) because:

The Pro Tama set was made of two components; the close up filter (I estimate +13) and the fisheye. When the fisheye is screwed in front of the closeup, it becomes a wide angle converter! The fisheye had a 67mm screw filter thread on the outside, while the Octagon did not.

The cons of the Pro Tama were that it was 58mm (meaning I had to get a 55-58mm step up ring, and adding space between lens and converter, causing stronger vignetting than the Octagon). The Octagon, when reversed, had awesome funky lateral chromatic aberration. You have to look through it to appreciate it; it stretches everything not in the center like you were entering warp speeds, and the whites bleed all sorts of pretty primary colors (as opposed to traditional CA, which just looks icky purple.)

The Pro Tama just stretches the sides but does not cause funky colors. 🙁

The close up filter is amazing; I can get 1:1 lifesize magnification when screwed on the 18-70mm at 70mm!


The Octagon, reversed, features awesome funky lateral chromatic aberration. The Pro Tama has the warping effect, without the funky colors. 🙁

The warping effect can be shifted, by tilting and shifting the reversed Pro Tama. Much like a Lens Baby!


Both converters had vignetting at 18mm. The simple reason being that they were designed for lenses that start at a measly 35mm; thus, it could widen that to a 35mm * 0.45 = 15.75mm, or 35mm * 0.7 = 24.5mm. The imaging circles at the back of the converters are not big enough for wider lenses.

I needed to zoom to 22mm at least, on my Sony 18-70mm F3.5-5.6 kit lens, to avoid vignetting. By then, with digital crop, it had already become 33mm… multiplied by 0.45 to get 14.85mm. Of course, I loved the vignetting and minor light falloff, so I used it wide and got 18mm * 0.45 = 8.1mm. Add the digital crop to get 12.15mm.

On the Olympus OM-2000 with Vivitar 24mm F2.0 lens things were more promising; there was still vignetting but 24mm * 0.45 = 10.8mm wide!

(I can’t show you shots from the Olympus because I haven’t finished my first ever roll of Fujifilm Velvia 100F.)

Through more usage, I had the sinking feeling that the wideangle converter was not really 0.45x; in application it was like a 0.7-0.8x. I haven’t figured out how to properly calculate it though, but the answer to the question is, “Yes, it is wide enough.

What if it was just the fisheye, since I could omit the 58mm macro element?


It becomes a close-up with fisheye barrel distortion! I had to shoot at F22 with flash to reduce out-of-focus-ness, even at infinity.


I also tried the Sony 11-18mm F4.5-5.6 DT lens. It was, well, disappointingly straight. (Though, that’s what people pay for.) I tried to coax some barrelling but none was obvious. This certainly wasn’t an artsy lens; the Sony 16mm F2.8 diagonal fisheye would have served that purpose.


I can’t tell if there is distortion, other than the stretching of faces towards the edges of the frame.

At 11mm, it was probably the sweetest at F5.6-F8. There was slight softness at my only 1/3rd of a second shot, and crispness at 1/6th. I attribute this decreased steadiness to me not holding it confidently like it was my own to sweat all over the rubber grip. Y’know how it is, once you’ve got the feel and grip of things your steadiness increases… so if I could get it to my 3.5-stop average I should get 0.8 seconds steady.

I have this nagging feeling that in-body stabilization really works better on the tele end, contrary to popularly propagated claims.

The camera knows the focal length from the lens, and it adjusts its corrections according to which lens is used. Real-world tests have confirmed that these in-body systems are just as effective as in-lens systems, even with longer lenses.

From a most informative Minolta AF/Sony Alpha F.A.Q., which is a great read even if you don’t have a Minolta/Sony SLR (especially the bit about focusing beyond infinity.)

Random Tip #1

My Sony 18-70mm F3.5-5.6 kit lens focuses slightly beyond infinity. However, all I need to do to set it to infinity is to turn the camera off and on! (The camera sets the lens to infinity even in manual focus.)

Random Tip #2


Default settings.

I lower the contrast to -2 and boost the sharpness to +2 by default on the Sony A100. You can always add contrast in Photoshop easily, and the +2 sharpness doesn’t seem to affect noise.


What I prefer.

The Sony A100 very predictably underexposes when there is backlight and is set to Multi-segment Metering, with Dynamic Range Optimizer Advanced on. It’s great that it’s predictable, so I can quickly bump the EV to +1 (with DRO+ keeping the highlights in check.)

And so, for a flatter but colorful backlit scene, I’d suggest setting contrast to -2, sharpness +2, saturation +1, EV +1.


Setting the contrast to +2 on the other hand, gives this.


I then pumped the EV to +2 to bring out the purple fringing in the trees.


I stacked my Hoya R72 52mm infrared-pass filter, and my Raydawn 52mm circular polarizer and linear polarizer, then the Pro Tama, to get this severely vignetted infrared shot. Quite cool, the internal reflection of flare.


I loved the gradual light falloff. The vignetting adds character to the picture, and I have to say I’ve never felt so inspired. Lines that extend from the center are least likely to be distorted.


At effectively 12.15mm I could afford to shoot at 0.8 seconds! (This was at F3.5 1/5s though.)

I paid under RM150 for the Pro Tama. Awesome deal, and a great way to stretch your creativity on just a kit lens alone! You get true life-size macro, a pseudo-fisheye, and a reverse-handheld tilt-shift lens!

9 thoughts on “Glass I

  1. flysheep Post author

    "+1 = 1000/1 = 1000mm = 100cm; +2 = 50cm; +4 = 25cm; +10 = 10cm; +25 = 4cm."

    is it +1= 1000/2 ?

    the mosque photo is nice. 🙂 yes, i prefer the contrast-2 too

    Reply
  2. Tan Yee Wei Post author

    If you want to test the multiplication of that wide-converter, mount it on a lens and observe two subjects located at opposite ends of the frame. Note the angle that between their lines of sight to you.

    Using some trigonometry, you can figure out the effective focal length, since you know that the film’s width is 36mm.

    Or if you want it here, find x that satisfies the following equation:

    tan (angle) = x / 18
    x = 18 * tan (angle)

    where angle is the angle that the two line of sights make, and 18 is obtained from 36/2.

    Reply
  3. Albert Ng Post author

    nORmAN: Architecture photographers would pay for good undistorted lenses.

    flysheep: No, +1 = 1000/1. +0 (which is no close up, at infinity) is 1000/0 = infinity! 😀

    Tan Yee Wei: Now to find a tiled floor and tripod. 😀

    Reply
  4. Tan Yee Wei Post author

    Or you can do it large scale by going somewhere with a good view of the city and taking the photo.

    Consult a map or Google Earth, and draw a triangle between your tower, the building at the right edge, and the building on the left edge.

    The errors introduced by your varying position on the balcony and the length of the lens barrel would be negligible.

    Reply

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