Carl Zeiss newsletter nr32_en_web

3132

Contents

Light in the Dark:

Fort Point San Francisco 2

Planar T* 1,4/50 ZE -

A Standard Lens with

a Difference 4

Manual Focusing with

AF Camera Systems 6

New York City Impressions

With the Distagon T* 2,8/21 12

July 2009Carl Zeiss Camera Lens Division

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Carl Zeiss July 2009

Camera Lens News No 32

Light in the Dark: Fort Point San Francisco

Directly under the famous San

Francisco Golden Gate Bridge is the

Fort Point National Historic Site. This

fort was built to protect the SF Bay

from the Confederate army during

the U.S. Civil War, though as far as

we know it was never used in military

operations. Today Fort Point is open

to visitors three days per week and

we have taken quite a few photos

there over the years.

The challenge taking interesting

photos at Fort Point is the high

dynamic range (light from the outside

and quite dark structures) and the

need for ultra wide angle lenses. We

deal with the high dynamic range

using HDR techniques (later more)

and the Distagon T* 2,8/21 ZF on a

Nikon D700 full frame camera was

ideal to photograph the interior

architecture. We were very pleased

that all the scenes we wanted to

capture could be photographed using

the Distagon T* 2,8/21 ZF lens. One

could say that 21mm seems to be

a very good focal length for indoor

photography in general. It has a

wide angle of view of 90° without

getting to the extremes. Wider angles

can lead to more distortions than we

would like to accept.

Taking HDR photos requires taking

multiple exposures from a sturdy

tripod. An example of a typical

exposure range is shown here:

For this kind of scene we need at least

3 shots with -2.0Ev, 0EV and +2.0EV

exposures (more could be even

better). As you can see in the middle

exposure, the shadows are too dense

and the highlights are blown-out.

Even the -2EV underexposed photo

still has slightly aggressive highlights.

The +2EV overexposed photo

shows good shadow detail, but the

highlights are lost completely. That

the Distagon T* 2,8/21 ZF is a manual

lens is not problem at all, because

these kind of photos are always

best shot using manual focus. We

generally used a hyperfocal setting

for the photos at Fort Point, because

there was not any interesting

detail closer than 2m and we used

f/8 for nearly all our photos.



We use the Photomatix software

to combine these three photos into

one HDR image. HDR images (32 bit

floating point) can store a tonal range

that is even much higher than we

needed in this case. What to do with

these HDR images if their content

cannot be printed on any medium?

The answer is Tone-mapping. We

use the Photomatix Details Enhancer

tone-mapping tool to map the larger

tonal range into a printable version.

Here is our result from this two-step

process (HDR generation and tone-

mapping):

The final image shows open shadows

and no clipped highlights. The next

photo was from the same session and

created using the same technique.

Overall we can report that the

Distagon T* 2,8/21 ZF on a full frame

camera and HDR with Photomatix

proved to be the right tools for our

work at Fort Point. We plan to work

more using this lens and apply its

angle view on our subjects.

After our session inside of Fort Point

we took this shot of the Golden Gate

Bridge just outside of Fort Point.

It shows that 21mm can be a very

creative focal range.

Text and photos by Bettina +

Uwe Steinmueller



The next test for the Planar T* 1,4/50 ZE

was a series of portrait shots I took

for a manufacturer of specialist

skateboards – so-called longboards –

in Dusseldorf. I had previously tended

to work with autofocus zoom lenses

and occasionally with autofocus

prime lenses, so the manual focus

took some getting used to at first,

Planar T* 1,4/50 ZE - A Standard Lens with a Difference

I had been toying for a while with

the idea of getting myself a 50 mm

prime lens, but with autofocus. That

was before I got the opportunity to

test the ZEISS Planar T*1,4/50 ZE with

manual focus, and now I wouldn‘t

change it for the world!

The first project for my new lens

was a fashion shoot on the topic

of „My home is my castle“, which I

worked on with the photographer

Thea Fischer. The location we used

was an old Russian military hospital

near Berlin. The shoot took place at

-5°C in snowy, icy conditions and

was a real challenge in so many

different ways, but it really showed

me just how much I could depend

on my new lens. I think the thing

that impressed me most about the

Planar T* 1,4/50 ZE was the superb

image quality it achieved even at

wide apertures.

The Planar T* 1,4/50 ZE also delivers

bright images with excellent contrast

and natural color rendition, a fact

that was particularly appreciated

on this shoot. The subjects really

come to life with the extreme con-

trasts between light and dark and

the exciting color contrasts. but I was impressed by the precision

of the available settings. The extra-

large rotation angle for high-precision

focusing provides major benefits for

all sorts of applications. Thanks to

these technical features, I had more

time to devote to each subject and

more control over the end result.

Fashion shoot „My Home is my Castle“ in collaboration with photographer Thea Fischer.



Both shoots showed me that working

with the Planar T*1,4/50 ZE makes

you more conscious of your image

composition. These photographs

ultimately have more of a sense of

harmony than photographs taken

with an autofocus zoom lens.

Personally, I came to the conclusion

that the Planar T* 1,4/50 ZE is the

perfect lens for me, not only thanks

to its superior image quality, but also

due to the broad scope for creative

design that the manual focusing

offers. When it comes to portrait

shots I prefer to be close to my

subject, and this lens is the ideal

choice for that technique. It may

take a bit of practice to speed up

the process of working with it, but

it is worth the effort. However,

one thing I would recommend is

swapping the ground glass screens

included with the lens for screens

with a split image rangefinder

and microprisms, since this makes

it far easier to check the focusing.

All the pictures here were taken

using a Canon EOS 5d and the

Planar T*1,4/50 ZE.

Portrait of a longboard manufactorer in Dusseldorf.

Sabrina Weniger obtained

a degree in pedagogy from

Dusseldorf‘s Heinrich-Heine

University. At the same time she

was taking photography courses at

colleges in Cologne and Dusseldorf

and attending workshops in digital

photography and image editing.

During a trip to New York City in

2004 as part of her studies, she

decided to live her dream of

becoming a photographer. A jury

consisting of photographers, press

representatives and members of

the “Photo+Medienforum Kiel”

chose her as the winner of the

Kiel Scholarship in 2005. Viewers

of her photos are immediately

struck by the natural, simple

pleasure that she takes in her

work, which features tranquil

moments enriched with a spirited

dose of joie de vivre.

Carl Zeiss July 2009 Page �


relevance for photography and image

reproduction.

Precision focusing

One of the key links in the chain of

successful image rendering is the

precision with which the lens focuses

on the main subject. Generally

speaking, a photographic lens only

provides optimum rendering at

maximum image quality of a two-

dimensional surface. This surface

runs exactly in parallel to the film or

sensor in the camera. Depending on

the magnification and the selected

aperture, a certain range both in

front of and behind the point of

optimum focus is also considered

to be „adequately sharp“. In this

context, the magnification refers

to the ratio between the image

produced by the lens and the object

being photographed. Thus, the focal

length of the lens, the shooting

distance and the size of the film or

sensor are responsible for the so-

called depth of field. The focusing

Manual Focusing with AF Camera Systems

region designated as the depth of

field is the extent of the range in the

object space of an imaging optical

system. This region is rendered in

acceptably sharp focus on the focal

plane.

You can read about the effect that

slight defocusing has on image

quality in the article „Measuring

lenses objectively“ which appears in

Camera Lens News no. 30 starting

on page 24. This article shows

how important precise focusing is

whenever a photographer intends to

produce big enlargements or requires

optimum quality for any other

reason, and not only when using

wide apertures.

What should I focus on?

The question of what main subject

to focus on obviously comes down

to the taste of each individual

photographer. Nevertheless, there

are not likely to be any significant

differences in opinion when it comes

to choosing the optimum focal point

for photographs of a painting or

of a mountain chain that stretches

into the endless distance. Equally,

traditional portrait photography

continues to reserve maximum

sharpness for the model‘s eyes.

Tinkering with sharp focus and blur

is one of the most fundamental

creative aspects of photography. The

fact that our environment is three-

dimensional means that people can

have differing views on what should

be depicted with clarity and what

should appear in a sketchy or blurred

form, for example when searching Photographer Sabine Unterderweide

Superb image quality in today’s

world of photography is fostered

by a whole host of different factors

such as the high numbers of pixels

in digital SLR cameras, large format

sensors in full-frame 35mm format

or traditional almost-medium

format, intelligent image processing

techniques and noise reduction

algorithms.

The results are also dependent on

how the camera interacts with the

lens, which is why high-grade optics

have such a vital role to play in

fulfilling photographers’ increasingly

sophisticated demands with regard

to image quality.

The weakest link

Achieving top-quality shots with

high-resolution cameras means

keeping all the parameters that have

a direct or indirect impact on image

quality within strict boundaries. The

idea that “a chain is only as strong

as its weakest link” has particular



for the right focus in a group of

people seated around a circular table

under difficult lighting conditions.

Checking the depth of field using

the camera‘s preview button is one

technique that can be useful. Good

results can also be achieved by the

use of face recognition software in

modern cameras that focuses the

lens on the nearest person, especially

when using compact cameras with

small sensors and short focal lengths.

However, this is clearly inadequate

for the purposes of carefully arranged

photography using SLR or rangefinder

cameras, where high apertures and

longer focal lengths are the norm. In

these situations, the photographer is

still required to choose the required

autofocus frame or select a subject

using the manual focus function. The

photographer‘s aim here is to create

a powerful, unique image. Any small

deviations in the focal plane could

potentially diminish the technical

achievement of the image or even

completely alter the impact of the

photo, whether deliberately or not.

Advantages of AF systems

Autofocus systems have undergone

major developments since they were

first introduced in cameras in the

1980s. Manufacturers have steadily

improved their systems‘ performance

and efficiency in daily use, and

the combination of an increasing

number of AF points in the camera

bodies and ultrasonic motors in

the lenses has facilitated fast and

smooth focusing for the phase AF

systems typically found in today‘s SLR

cameras. For some applications, it is

precisely this speed that marks the

key benefit over other AF methods

such as the contrast-based AF

typically found in digital compact

cameras or manual focusing.

Good AF systems can generally

achieve a very high number of

„hits“ in terms of the sharp images

they produce with long telephoto

lenses in situations such as taking

shots of cheetahs in the wild,

snapping celebrities from within a

pack of paparazzi or photographing

footballers on the playing field.

So is there any place left

for manual focusing?

For any subject that is either not

actively moving away from the

photographer‘s position or that is set

to move into the “trap focus” after

careful pre-focusing, better results

can be achieved with careful manual

focusing. Carefully framed landscape

shots, images of buildings or

architectural details and meticulously

arranged tabletop displays in a

photographer‘s studio are unlikely to

require the use of autofocus.

Equally, both spontaneous portraits

and reportage shots can achieve the

same focusing precision by manual

means as by using an AF system.

Macro shots of butterflies on a

flower that require a very shallow

depth of field – where a tripod is

generally a sensible choice – should

always be precisely focused using

manual methods. In these cases,

it is rare for any of the camera‘s

AF points to coincide exactly with

the photographer‘s choice of focal

point and, all too frequently, the

focusing point covers too much of

the subject with a large extension

of depth, which means that it is no

longer possible to use the automatic

mechanism to achieve precise focus.

Were older cameras and

lenses actually better?

Anyone who has attempted to

manually focus modern AF SLR

cameras and their corresponding

AF lenses will have quickly come

to the sobering conclusion that,

practically speaking, this is far from

easy. Steep-pitch helical mounts,

play and backlash in the focus rings

of the lenses, dim viewfinders and

Photographer Michael Ankenbrand



far-from-suitable screens in the

cameras make it very difficult to

achieve high-precision focusing. In

contrast, it is quite a revelation to go

back to one of the good SLR cameras

with a suitable lens from the era

before the widespread introduction

of AF systems and witness the large,

bright viewfinder, the eminently

practical adjustment aids on the

screen and the way in which a

subject seems to „spring to life“

when it is correctly in focus.

Few of today‘s cameras achieve

the innate viewfinder quality of

these analog models that have now

entered into the annals of history.

Nevertheless, some good digital

camera models from the medium

to top-class brackets, especially

full-frame cameras, do offer some

advantages for high-precision

manual focusing, at least thanks

to the glass prism in the viewfinder

and corresponding viewfinder

magnification.

What is the difference between

AF and MF lenses?

In terms of how lenses handle

manual focusing, even good-quality

AF lenses cannot offer the level of

precision of a simple manual focus

lens. The micro-motor in the lens

or in the camera requires a small

rotation angle and extremely smooth

action if it is to have any chance of

turning the focus ring and setting

the focus rapidly and quietly. This

is one instance where speed takes

precedence over accuracy! It is

therefore hardly surprising that cine

lenses for the Hollywood film industry

are focused manually and have no

autofocus option. If the lens has to

be operated remotely during filming

due to the camera being mounted in

an inaccessible spot, powerful servo

motors engage with the outermost

toothed rings of the lens. These are

powerful enough to precisely rotate

the focus ring with extraordinary

smoothness.

Manual photographic lenses

Nowadays, almost all manufacturers

only offer AF interchangeable lenses

and some systems – such as the

Canon EOS system – have never

even featured manual lenses at all

(apart from a few specialist models).

The current range of Carl Zeiss SLR

lenses incorporates some of the

expertise we have acquired from

our professional cine lenses. With

large rotation angles (e.g. almost

3�0 degrees in the case of the

Makro-Planar T* 2/100 from infinity

to the close-up limit of 0.44 m), a

Photographer Tobias Zehnder

On the set of Tom Tykwer‘s ‚The Perfume‘.



wealth of available settings for

the all-metal unit and none of the

constraints caused by the need

to turn a focus motor, these lenses

achieve a level of focusing

accuracy that is far superior to any

conventional AF lenses. Thanks to

the popular range of lens mounts

comprising the ZF (Nikon F bayonet

mount), ZE (Canon EF bayonet

mount) and ZK (Pentax K bayonet

mount), the lenses can be directly

employed on suitable cameras at

high levels of functionality without

requiring an adapter.

AF cameras with MF lenses

This leads us to the question of how

far this accuracy can also be achieved

using modern (D)SLR cameras, most

of which suffer from the limitations

described above in comparison

to „old“ models without AF. The

focusing screens fitted as standard

to modern autofocus cameras are

primarily designed for a bright,

crystal-clear viewfinder. What they

generally lack, however, are optical

focusing aids (e.g. split image

rangefinder and microprisms) and

– due to their surface structure – the

ability to make any viable distinction

between „in focus“ and „out of

focus“. In addition, AF focus points

and other markings that appear

either on a second screen positioned

above or on an LCD display can make

it hard for the eye to clearly check the

focus on a single plane of the screen.

Other types of screens

By replacing the focusing screen with

a variant that has been optimized

for manual focus, it is possible to

achieve some major improvements.

This procedure can be carried out for

all SLR camera models, even if the

manufacturer claims otherwise and

fails to offer any interchangeable

focusing screens. For example,

Canon offers a choice between the

EC-A (with microprism ring) or EC-B

(with split image rangefinder) for

the models from its EOS-1 range.

Meanwhile, the EOS 5D and 5D MkII

have the option of the Ee-S screen,

though this does not feature any

focusing aids and therefore offers no

significant benefits over the screen

fitted as standard.

Both these lenses and smaller

models such as the Canon EOS 50D

and 40D, Nikon models up to the

D700 and DSLRs from Pentax and

Fuji can be fitted with excellent

focusing screens produced by other

manufacturers who offer variants

that have been specifically tailored to

each specific model. By following the

manufacturer‘s instructions and, in

some cases, using the supplied tool,

camera owners can carry out the

replacement of the screen themselves

without too much trouble as long as

the process is carried out carefully

in the most dust-free environment

available.

Replacement focusing screens

are available from the following

companies:

www.katzeyeoptics.com

www.photoproshop.com

www.intenscreen.com

http://haodascreen.com/Canon5D.

aspx

One problem, however, is that the

screen and/or the mirror are often

not perfectly aligned in many new

cameras, and it only takes a minimal

deviation (less than 1/100th to 1/10th

of a millimeter) to produce a visible

focus error (front focus or back

focus). As long as the user continues

to work with the AF system of the

camera and default focusing screen,

this minor error is generally not

conspicuous. However, if the screen

is replaced with a variant that

includes focusing aids, then the

deviation becomes visible.



The only action that can be taken in

the face of this dilemma is to send

the camera to the manufacturer or an

authorized service center and request

that they align the screen properly.

For many camera models, aligning

the focusing screen involves inserting

or removing the corresponding

number of thin layers of film.

Electronic focusing aids:

fast, but not always perfect

In most of the Canon EOS, Nikon

AF and Pentax AF cameras, whether

digital or analog, electronic focus

confirmation continues to be

available even when using our ZE, ZF

or ZK lenses. The camera confirms

that the manual focus is correct by

illuminating the focus confirmation

light or the active AF point. In

many of the Nikon models (e.g.

the D700 and D3 series), additional

support is provided by two arrows

in the viewfinder which indicate the

direction of rotation for the focus

ring when performing fast manual

focusing.

However, these electronic focusing

aids only actually provide a relatively

imprecise means of achieving high-

precision manual focusing. The

region shown as „in focus“ when

rotating the focus ring is generally

quite large and is also dependent

on the direction from which the

subject is being brought into focus

(i.e. whether you are coming from

infinity or from the closest focus

distance). We therefore recommend

comprehensively testing the camera

in combination with a manual lens

in order to get a photographer‘s feel

for the situations in which you can

rely on the AF indicator. Especially

when using fast lenses, it is advisable

to take a bracketing series with

a wide-open aperture and short

shooting distances in order to achieve

optimum results.

It is sometimes possible to fall wide

of the mark when taking shots

with the aid of the focus confirmation

function, but fortunately some

recent camera models (e.g. the

Nikon D300, D700, D3 series and

the Canon EOS 5D MkII) have

incorporated an AF fine-tuning option

in the menu which obviously also

takes effect on the focus indicator

during manual focusing. If the

AF indicator consistently gives an

incorrect response when a certain

type of lens is used or even with

all lenses, then the focus error can

generally be rectified by carrying out

meticulous checks and adjustments.

Live View mode

Many of the latest DSLR cameras

enable a live image to be viewed on

the display prior to taking the shot.

It is usually possible to zoom into

this view far enough to carry out

focusing with great precision. Since

the camera‘s mirror has to be locked

up in this mode, the AF function

is either no longer available or the

mirror has to be briefly flipped down

and then back up again to carry out

focusing, depending on the specific

camera system. A further option is

the rather cumbersome contrast-

based autofocus function used in

compact cameras.

With the camera mounted on a

tripod and zoomed into the Live

View, a high-precision MF lens

enables accurate focusing. In addition,

Live View generally provides a bright,

crystal-clear image even in poor light.

Alignment tolerances of the focusing

screen, the mirror or the entire AF

system of the camera are no longer an

issue if Live View is used for manual

focusing. At least in those cameras

that take the preview image directly

from the image sensor, you see the

allocation of the focus exactly as it

will subsequently appear in the shot.



Focus shift

Yet even with a perfectly aligned

focusing screen with focusing aids,

autofocus that is cleanly aligned

or adjusted using the camera‘s

menu and the Live View function,

it is impossible to guarantee proper

checking of the focus prior to

shooting in every single case.

Spherical aberration in lenses leads

to so-called focus shifts. This term

refers to the fact that changing

the aperture causes a shift in the

optimum focus position. This effect

is particularly conspicuous in the case

of fast prime lenses. You can find a

more detailed description of focus

shift in the article „Measuring lenses

objectively“ which appears in Camera

Lens News Nr. 30 starting on page 24.

In order to take into account the

effect of focus shift on precise

focusing, the user should – as far as

possible – carry out focusing at the

aperture at which the shot is sub-

sequently to be taken. Nevertheless,

there are still a number of limitations

to be considered: AF systems in

current camera models do not take

into account the focus shift of the

lens. This means that the reliability

of the AF indicator varies depending

on the type of lens, f-stops and

shooting distances.

Due to their surface structure,

focusing screens in fast lenses are

not capable of factoring in all the

incoming rays. This can easily be seen

from the fact that – depending on

the design – the brightness of the

focusing screen no longer changes

with lenses such as those that are

faster than 1:2.8. This means that

the change in the optimum focus

position can no longer be evaluated

on the focusing screen at wide

apertures when using very fast

lenses.

And there is also a “fly in the

ointment” when it comes to the use

of the Live View function, namely

the fact that many current camera

models (e.g. the Nikon D700 and the

Canon EOS 5D MkII) automatically

control the aperture in the Live View

mode based on the set ISO values

and the ambient light in order to

ensure that the image in the display

is consistently shown with the correct

brightness and contrast values. This

means that it is no longer possible

to close the aperture to the desired,

fixed setting using the preview

button. Correct evaluation of the

depth of field and focus position is

therefore equally out of reach using

this method, since the aperture is

only closed to the desired setting

when the shot is actually taken.

Conclusion

When your aim is to take

photographs with wide apertures and

extremely accurate focusing, high-

precision manual lenses can make

your work easier. Enhanced focusing

screens, a well-aligned AF system

and use of the Live View mode all

help to make focusing more precise.

Although the influence of focus shift

cannot be ignored, it can produce

better, reproducible results if suitable

care is taken. In situations where

focusing accuracy is of paramount

importance, it is also advisable

to take finely graded bracketing

sequences.



The Carl Zeiss Distagon T* 2,8/21 has

given us the confidence we need to

take truly uncompromising shots with

a wide-open aperture.

A reliable wide-angle lens is an

absolute must when you are trying to

capture the hectic street life of New

York. It paves the way for capturing

the city’s atmosphere together with

its sophisticated architecture – that

very special combination that makes

the metropolis of New York City so

very unique.

New York City Impressions With the Distagon T* 2,8/21

We primarily used the

Distagon T* 2,8/21 to shoot highly

contrasting street scenes at night

under tricky lighting conditions.

Once again, we achieved some

stunning results. Focusing was smooth

and consistent and it made it

absolutely clear that the composition



Camera Lens News

A newsletter for all who use, buy, sell, like,

report about and are interested in Carl Zeiss

camera lenses.

All information in Camera Lens News is

accurate to the best of our knowledge at

the time of publication.

Publisher:

Carl Zeiss AG

Camera Lens Division

Marketing

7344� Oberkochen

Germany

Phone: +49 (0) 73�4/ 20-�175

Email: [email protected]

Internet: www.zeiss.de/photo

Shoot Studio The combined

talents of Shoot Studio‘s four

photographers, Jean-François

Gratton, Pierre Manning, Martin

Girard and Jean-François Lemire

deliver powerful advertising,

cultural, corporate and editorial

photography. Supported by

an outstanding team, Shoot

Studio unites a prolific group of

artists who strive to discover the

unexplored through technology

and personal development.

of the image was entirely in our

own hands.

In addition to the street shots, we

also tested out the macro capabilities

of the lens using this cutlery basket.

The meticulous precision of the

Distagon T* 2,8/21 really came to

the fore here, allowing us to bring

subjects very close to the lens.

Carl Zeiss newsletter nr32_en_web

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