Sunday, June 30, 2013


Nikon S2, 5cm f/1.4 S.C.

Saturday, June 29, 2013

Numerology of fast lenses

Like most photographers, I fetishize depth of field isolation and fast lenses.

I have mentioned effective maximum aperture before, but wanted to muse about it some more. Recall that f/stop is calculated as (focal length)/(aperture), so one can recover the effective aperture (abbreviated E.A. below) of a x mm f/ y lens by x / y. Thus a 50mm f/2 lens has effective aperture 50/2 = 25mm.

The effective aperture more or less determines the depth of field, although focus distance also matters - the closer you are to your subject the less depth of field there will be. This makes comparing the depth of field between lenses of different focal length more complicated, since presumably one would change the camera to subject distance to maintain the same framing. I know there are formulae for blur circles, and some day I will actually do the calculations for depth of field of various lenses assuming they are framed for say, a human head. Edit: It looks like the calculators here and here will do what I want. For the time being, effective aperture will an approximation of the possible depth of field isolation of each lens.

Here are two links which suggest that if you maintain the same framing, then depth of field does not change with focal length: Luminous Landscape
Cambridge in Colour
However, the blur in the background seems different, perhaps due to perspective? Will need to think about this some more. It would be easier if I just had all the fast lenses sitting around to try out...
In any case, here is a list of the effective apertures of various fast lenses:

Lens E.A. (mm)
50mm f/2 25
35mm f/1.4 25
50mm f/1.8 27.8
35mm f/1.2 29.2
200mm f/5.6 35.7
50mm f/1.4 35.7
105mm f/2.8 37.5
135mm f/3.5 38.6
50mm f/1.2 41.7
105mm f/2.5 42
85mm f/2 42.5
85mm f/1.8 47.2
135mm f/2.8 48.2
50mm f/1 50
200mm f/4 50
105mm f/2 52.5
300mm f/5.6 53.6
105mm f/1.8 58.3
85mm f/1.4 60.7
180mm f/2.8 64.3
300mm f/4.5 66.7
135mm f/2 67.5
85mm f/1.2 70.8
200mm f/2.8 71.4
400mm f/5.6 71.4
300mm f/4 75
200mm f/2 100
300mm f/2.8 107.1
400mm f/3.5 114.3
500mm f/4 125
800mm f/5.6 142
400mm f/2.8 142.8
600mm f/4 150

A few lenses should surprise you - 135mm f/2.8 (48.2), 200mm f/4 (50), and slow f/5.6 or f/4.5 300mm (53.6-66.7) lenses have fantastic depth of field isolation possibilities and can be acquired cheaply. I'd rub this in the face of anyone who bought a $11,000 50mm f/0.95 (52.6) Noctilux. That said, there are of course advantages to the fast 50mm lens over the slower, longer lenses. The longer lenses are bigger and heavier, require more space between you and the subject, are much more difficult to hand hold, and cannot shoot in as low light.

But if you want to play with shallow depth of field on a budget, and shoot in decent light, go get a 135mm f/2.8!

It occurs to me there is a fairly natural way to measure a lenses low-light ability, accounting for both the maximum aperture and the focal length of the lens by using the "1/focal length" rule of thumb. Namely one can compare the minimum handholdable exposure value or EV one can achieve with the lens.

Lens EV
21mm f/1.4 5.4
24mm f/1.4 5.6
35mm f/1.2 5.6
50mm f/1 5.6
28mm f/1.4 5.8
35mm f/1.4 6.1
50mm f/1.2 6.1
24mm f/2 6.6
50mm f/1.4 6.6
14mm f/2.8 6.8
28mm f/2 6.8
85mm f/1.2 6.9
16mm f/2.8 7.0
35mm f/2 7.1
20mm f/2.8 7.3
50mm f/1.8 7.3
85mm f/1.4 7.4
24mm f/2.8 7.6
50mm f/2 7.6
28mm f/2.8 7.8
35mm f/2.8 8.1
85mm f/1.8 8.1
20mm f/4 8.3
85mm f/2 8.4
105mm f/1.8 8.4
105mm f/2 8.7
135mm f/2 9.1
105mm f/2.5 9.4
105mm f/2.8 9.7
200mm f/2 9.6
135mm f/2.8 10.0
180mm f/2.8 10.5
135mm f/3.5 10.7
200mm f/2.8 10.6
300mm f/2.8 11.2
200mm f/4 11.6
400mm f/2.8 11.6
300mm f/4 12.2
400mm f/3.5 12.3
200mm f/5.6 12.6
300mm f/4.5 12.6
500mm f/4 13.0
300mm f/5.6 13.2
600mm f/4 13.2
400mm f/5.6 13.6
800 f/5.6 14.6

I think this helps explain why the super fast 50mm lenses are in such demand - they offer the highest possible shutter speed at any given light value to help stop motion, plus a large effective aperture, and no other lens except for 21mm f/1.4 and 35mm f/1.2 give you the ability to handhold in low light.

Comment: Given nominal exposure indoors (about as dark as I'd want to be able to handhold) with ISO 400 film is like 1/30 @ f/2.8 I'd say lenses with EV above about 8 are decent enough for low light handheld shooting.


Nikon S2, 5cm f/1.4 S.C.

Friday, June 28, 2013

Focus on AI versus AI-S Nikkor lenses

Why you should buy AI lenses instead of AI-S lenses, and save money in the process:

If you are like me and love the classic manual focus Nikkors (ignoring for now the non-AI lenses which can be used on fewer cameras), then you know there are two subtly different mounts, the automatic indexing AI mount and the slightly newer, slightly more intricate AI-S mount.

When shopping for lenses, you will often see (what appears to be) the same lens in both AI and AI-S mount, and it will usually be cheaper in the AI mount. Why are the AI-S lenses more expensive? They are slightly newer, but the Nikkor lenses are built to last, so if you can find your desired lens in good condition in both AI and AI-S mounts, which should you choose?

From afar, it is usually impossible to tell the difference between the AI and AI-S versions of a lens. Generally the optics and overall cosmetics are the same, (although the focusing scales tend to be on the black barrel on AI lenses and on the silver grab ring on AI-S lenses - I find the AI-S lenses generally a bit better looking) but the mechanics differ slightly. The quickest way to identify an AI-S lens from an AI lens is that AI-S lenses always have the smallest aperture written in orange and a small semi-circular (in cross-section) notch cut out of the back of the mount.

There are very specific instances when AI-S lenses will work better with specific bodies in specific modes. AI-S lenses will work slightly better if shot in shutter priority and program mode on the few bodies which support them, and long (135mm + ) lenses can tell certain bodies to use "P-Hi" mode which prioritizes faster shutter speeds to help you hand-hold the longer lens. Personally I know I will never be in a situation where having an AI-S mount instead of an AI mount will matter to me.

I have long understood that there is usually very little reason to pick an AI-S lens over an AI lens, all else being equal. But recently I realized there is often a very good reason to pick the AI lens: they almost always have a longer focus throw.

There may be shooting situations where you might prefer having a shorter focus throw for faster focusing, but in those instances you'd probably be better off with an automatic focusing lens anyway. I posit for the longer and faster lenses, and for the more meticulous shooters the AI lenses with longer throws are the better purchase.

Below I have listed the differences between AI and AI-S versions of lenses. I hope these help you make an informed decision. If a specification is not listed then the AI and AI-S versions are otherwise identical or the differences are negligible.

20mm f/3.5
AI: 100° throw
AI-S: 70° throw

This lens is wide enough and slow enough that an extra 30° throw probably is not worth worrying about, but the AI version is still cheaper.

24mm f/2.8
AI: 160° throw
AI-S: 60° throw

I have the AI-S version and I would very much like the longer focus throw of the AI version. It may be surprising with a wide and not-very-fast lens that precise focusing is a problem, but I do have trouble nailing focus with the AI-S version.

24mm f/2
AI: 160° throw
AI-S: 80° throw

28mm f/3.5
AI: 200° throw
AI-S: 90° throw

28mm f/2.8 - not the same lens!
AI: 190° throw, (7/7), 0.3 meter close focus, does not have CRC
AI-S: 170° throw, (8,8), 0.2 meter close focus, has CRC

The AI-S version is generally (universally?) viewed as the better lens, and I love the close focus ability. However, I haven't tried the AI version.

28mm f/2
AI: 120° throw, 0.3m close focus, 7 curved blades
AI-S: 120° throw, 0.25m close focus, 7 straight blades

I'd get the AI-S version for the slightly closer focus.

35mm f/2.8 - careful!
AI "old": (6/6), 195° throw
AI "new": (5/5), 100° throw
AI-S: (5/5), 120° throw

I am not certain how you distinguish between the two AI versions (besides the length of the focus throw) or which is held in higher regard optically. This is the one case where the AI-S version of a lens has a longer focus throw.

Even more interestingly, Nikon's Thousand and One Nights goes through the designs of the various 35mm f/2.8 SLR lenses, starting with the original (7/5) design (3.5cm f/2.8 S non-AI), to the classic (7/6) design (35mm f/2.8 S non-AI) to the (6/6) design of the "old" AI-design, but omits the latest (5/5) design in the "new" AI lens, which is shared by the AI-S version.

35mm f/2
AI: 190° throw
AI-S: 120° throw

It seems many people think the f/2.8 or f/1.4 lenses are better.

35mm f/1.4
AI: 180° throw, 7 blades
AI-S: 105° throw, 9 blades

I'd get the AI version and live with "only" a 7-bladed aperture. At f/1.4 I think the extra focusing precision would be worthwhile. The cosmetics differ slightly, the front of the AI is conical where as the AI-S is (to me) more aesthetically appealing.

50mm f/1.8
AI (older style): 210° throw
AI-S (older style): 130° throw

50mm f/1.4
AI: 210° throw
AI-S: 140° throw

50mm f/1.2
AI: 180° throw, 7 blades
AI-S: 110° throw, 9 blades

I'd get the AI version and live with "only" a 7-bladed aperture. At the wider apertures I think the extra focusing precision would be worthwhile.

58mm f/1.2 Noct
AI: 230(?)° throw, 7 curved blades
AI-S: 140° throw, 9 straight blades

I'll never be able to afford one (or find one) but hypothetically I'd get the AI version and live with "only" a 7-bladed aperture.  At the wider apertures I think the extra focusing precision would be worthwhile.

85mm f/2
AI: 255° throw
AI-S: 170° throw

105mm f/2.5
AI: 170° throw, no built-in hood, 7 curved blades
AI-S: 140° throw, built-in hood, 7 straight blades

These two look different cosmetically. I may get the AI-S version for the completely shallow reason of looks (like the 35mm f/1.4 AI the 105mm f/2.5 AI has a sort of conical front) and built-in hood, but the slightly longer focus throw of the AI might make it worth considering.

135mm f/3.5
AI: 220° throw
AI-S: 180° throw

135mm f/2.8
AI: 270° throw
AI-S: 180° throw

135mm f/2
AI: 270° throw
AI-S: unknown throw

I'd probably get the AI version - it ought to be cheaper and it is unlikely the AI-S has a longer throw.

180mm f/2.8 - not equivalent lenses!
AI - no ED glass, (5/4)
AI-S - ED glass, (5/5)

I'd certainly get the AI-S version with ED glass.

200mm f/4
AI and AI-S have same specs.  Might as well get the cheaper one.

300mm f/4.5 (non-ED)
AI: 4m close focus, 6 blades, f/22 min aperture
AI-S: 3.5m close focus, 7 blades, f/32 min aperture

It is really better to save up more for the ED-IF version (skipping the ED non-IF AI version in between).

300mm f/4.5 ED-IF
AI: 7 blades, f/22 min aperture
AI-S: 9 blades, f/32 min aperture

I would get the AI-S version.

If you want to know more about the variations on the Nikon F mount, check out
By Thom
Camera Quest
KEH blog
Nikon USA
Ken Rockwell

All the information above was culled from the Photosynthesis site which has a fantastic and amount of obsessively gathered information on Nikon lenses.


Nikon S2, 5cm f/1.4 S.C.

Thursday, June 27, 2013

Wednesday, June 26, 2013

Tuesday, June 25, 2013


Nikon S2, Nikkor 5cm S.C. f/1.4.

Monday, June 24, 2013


Nikon S2, Nikkor 5cm S.C. f/1.4.

Sunday, June 23, 2013


Nikon S2, Nikkor 5cm S.C. f/1.4, missed focus.

Saturday, June 22, 2013


Leica IIIf, Canon 135mm f/3.5, weird shutter issue probably caused by cold and/or gloves interfering with shutter knob.

Friday, June 21, 2013


Leica IIIf, Canon 135mm f/3.5.

Thursday, June 20, 2013


Leica IIIf, Canon 135mm f/3.5.

Wednesday, June 19, 2013


Leica IIIf, Canon 135mm f/3.5.

Tuesday, June 18, 2013


Leica IIIf, Canon 135mm f/3.5

Monday, June 17, 2013

Sunday, June 16, 2013

Lens Baby Muse with Plastic Optic

Lens Baby Muse with Plastic Optic

Filter size: 37mm (bizarre)
Close focus: nominally a foot (can stretch out the lens to focus closer)
Aperture range: f/2 - f/8 included, also make-your-own kits available.
Aperture: round included, also make-your-own (hearts, stars, etc.)

Comments: A fun lens to mess around with.  You pull the end of the lens towards you to focus closer and bend the lens to adjust the 'sweet spot' i.e. what area of the frame is in focus, much like using tilts on a view camera.  The aperture use use affects how much is 'in focus'.  You change the aperture by switching out small magnetic disks with the included tool.  I'd recommend around f/5.6 for most uses.  Anything smaller and your viewfinder will probably be too dark anyway, and with the plastic optic at least, anything wider than f/4 will be too dreamy.

I do have a basic accessory kit with the creative aperture kit, telephoto, wide-angle, and close up lenses.  I find the telephoto lens vignettes a bit too easily, even on DX bodies.  I did make a pinhole from one of the aperture disks which is fun.

If I had to do it again I would start by buying the higher end Composer body and double glass optic to start with, but investing a lot of money on a toy/novelty lens seemed like a bad idea at the time.  It's not a bad idea to try one out first, but I wouldn't be afraid to spend a bit for for the better models.  The Lens Baby can really help you out of the photography doldrums.

More info: Lens Baby site

Some sample photographs follow.  Please note these were shot with digital and film bodies, and some with accessory wide/tele adapters and custom aperture disks.

More photos from this lens