Something About The Depth of Field

First, I have to introduce you a few concepts before move on the calculation of the depth of field.

1.Focus
A point toward which light rays are made to converge after passing through a convex lens.

2. Circle of confusion
Optical spot caused by a cone of light rays from a lens not coming to a perfect focus when imaging a point source.It is the largest blur spot that will still be perceived by the human eye as a point.

3.Depth of Field 
Distance between the nearest and farthest objects in a scene that appear acceptably sharp in an image. Changes by changing the focus, aperture value or the distance between the subject and the camera.  

The bigger the lens aperture, the smaller the depth field and vice versa.

The longer the lens focus, the smaller the depth of field, and vice versa.

The farther the distance, the bigger the depth of field. 

4.How to calculate the depth of field 
δ: diameter of circle of confusion
f: focal lengh
F: aperture value of the lens
L: focus distance
ΔL1: front depth of the field
ΔL2: back depth of the field  
ΔL: depth of the field

                FδL²  
ΔL1= ——————    (1) 
            f² + FδL  

                FδL²
ΔL2=  ——————    (2)
             f² - FδL 

                                         2f²FδL²

ΔL =	ΔL2 + ΔL2  = ———————

                                      f⁴ - F²δ²L² 

 The back depth of th field > front depth of field  

Some thing about telelens DC

A telelens is a  long-focus lens in which the physical length of the lens is shorter than the focal length.
Although telelens DC has many advantages, it will require more skills, higher quality of big zoom lens and higher ability to resist dispersion.

I will introduce some well known model.

1.Sony Cyber-shot H1

Cyber-shot H1 is Sony's attempt to win a share of one of the fastest growing digital camera market sectors, the 5 megapixel 'super zoom'. Although Sony has produced big zoom cameras before, the H1 is the electronics giant's first foray into compact, big zoom image-stabilized cameras. As well as a huge 12x optical zoom the H1 is a real treasure chest of photographic control, offering a wealth of automatic, semi automatic and manual exposure modes, a big 2.5" screen and captures VGA/30fps movies in space-efficient MPEG format.

·                     5.1 effective megapixels

·                     36-432mm equivalent (12x optical) F2.8-3.7 zoom lens

·                     2.5” LCD (115,200 pixels)

·                     Full photographic control

·                     Optional wide and tele lens converters

·                     Scene selection (7 modes)

·                     32MB internal memory, plus a Memory Stick/PRO slot

 2.Canon PowerShot S2 IS

 S2 is no 'minor upgrade' - almost every aspect of the S1's specification and performance has been improved or refined, the body is entirely new and some of the most serious problems found on the original model have been addressed.

·                     12x optical zoom (36-432mm equiv.)

·                     5.0 million effective pixels

·                     1.8-inch tilt-and-swivel LCD monitor

·                     Color electronic viewfinder

·                     Optical Image Stabilizer (3 modes)

·                     Ultrasonic motor (USM)

·                     Extra-long movie mode with enhanced VGA resolution and stereo sound

·                     Canon DIGIC II processor with iSAPS

·                     PictBridge and Canon Direct Print compatible – no PC required

·                     Six new 'special scene' shooting modes 

3.Panasonic Lumix DMC-FZ5

FZ5 has a range of relatively minor changes over the FZ3, including longer battery life, a repositioned shutter release and improved grip design, larger LCD screen, orientation sensor and a new fast focus mode, which Panasonic claims gives a 30% improvement on the previous model.

·                     5.0 million effective pixels

·                     36 - 432mm (equiv.) F2.8-3.3, 12x Leica DC VARIO-ELMARIT Zoom Lens

·                     Mega O.I.S (optical image stabilisation)

·                     New orientation sensor

·                     Venus II image processing engine

·                     9 scene modes and full photographic control

·                     TIFF mode

·                     Ultra-fast startup, focus, shutter lag and shot-to-shot time

·                     'Simple' mode for novice photographers

4.Konica Minolta DiMAGE Z5

 Latest addition to the big-zoom DiMAGE Z range to feature the CCD-shifting Anti-Shake system seen on the A2/A200 and Maxxum 7D Digital SLR. Aside from a 5MP sensor and a couple of minor specification tweaks, the DiMAGE Z5 is almost identical to the Z3.

·                     12x optical Mega Zoom and 4x digital zoom

·                     CCD-shift Anti-Shake System

·                     Fastest-in-class*1 Rapid AF with Predictive Focus Control

·                     5.0-megapixel CCD

·                     CxProcess III image processing technology

·                     High-resolution, shake-free VGA movies

·                     Large 2.0-inch LCD, compact body, and fast response

·                     Super Macro mode for shooting subjects as close as 1 cm from the lens

Unpack Leica Noctilux 50mm F0.95 ^_^

Bought last month... forgot to post it.

Unpacked~~~Passport + everything else

  

The lenses and the case~~~~~

  

Same as the last version, Built-in Hood, but full metal makes it smoother

  

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 With Leica M9

  

With F1

  

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Picture took by F1, with all apertures open

  

Pictures took by F0.95

  

Two reasons to buy this F0.95

1- Even noctilux 50 F1 IV is also built-in hood, but it is a little bit loose and this is a common problem.

2- The focusing ring is VERY tight. 

Canon's new EOS C300 and EOS C300 PL camcorder

* 8.3mp 2160×3840 Super-35 CMOS sensor (4K resolution)
* DIGIC DVIII Processor
* Canon XF Codec
* Dual Compact Flash Slots
* Exposure and focus are both manual only
* Announced date： January 2012
Price: $20,000 

New zoom lenses (PL & EF)
* Canon Zoom Lens CN-E14.5-60mm T2.6 L S
* Canon Zoom Lens CN-E14.5-60mm T2.6 L SP
* Canon Zoom Lens CN-E30-300mm T2.95-3.7 L S
* Canon Zoom Lens CN-E30-300mm T2.95-3.7 L SP

Three prime lenses
* Canon Prime Lens CTZ-029 (24mm)
* Canon Prime Lens CTZ-030 (50mm)
* Canon Prime Lens CTZ-031 (85mm)

TOO EXPENSIVE!!!