Cross polarising technique

The cross polarising techniques is a simple one to create. Just place a polarising filter in front of the lens and photograph a stiff plastic object in front of an LCD computer screen.  To illustrate the tip I attached a Hoyarex Linear Polarising filter* to the front of a digital camera.  Hoyarex polariser

I then positioned a plastic cereal container in front of my computer monitor (make sure the background is neutral grey and not a screen saver ) and mounted the camera on a tripod. You can hand hold if there’s enough light to get a camera shake free photo.
cross polarising technique

When you rotate the polariser you will see a rainbow of colour with the background colour of the monitor.

polarised cereal container

As you rotate the colours will become stronger and the background will go black.

polarised cereal container

I repeated the technique using a plastic wine glass

polarised wine glass

polarised wine glass

polarised wine glass stem

* Any polarising filter can be used – linear or circular . We have a selection for sale here in both screw in and system filters. Polarising filters for sale. The system filters are more practical as you can use one filter with a variety of lenses with different filter threads. Just get the filter, a holder, and a range of adaptor rings for the holder to attach to different lenses.

How to tell which Rollei Bayonet filter mount

There is much confusion when trying to fathom which vintage filter to buy for a Twin Lens Reflex camera that has a bayonet mount such as a Rolleiflex or Yashicamat. The reason is there are three sizes. Rollei Bayonet I Rollei Bayonet II and Rollei Bayonet III. The Bayonet I is sometimes described without the I because there wasn’t a Bayonet II or Bayonet III when it was introduced.

Well wouldn’t it be easy if all filters were marked with Bay-1, Bay-2 or Bay-3? Life’s not that simple!

To make things confusing manufacturers often left off these simple markings on their filters. And to make things even more confusing they added measurements in mm so a Bay-1 filter may be marked 28.5mm, which doesn’t seem to relate to its diameter. And to add icing to the confusion these filters were often renamed B30 or B-30.

So to help here’s our interpretation of the system and an easy way to check if the filter you have found on ebay or in the junk shop, flea market, antique centre, camera shop is the one you need.

Bayonet 1
Also known as: Bay I / B30 / B-30
Outer measurement: 37mm
Inside diameter: 30mm
Sometimes marked: 28.5mm
Fits: Rolleicord and Rolleiflex (with f/3.5 Tessar / Xenar), Yashica EM, Yashicamat, Yashicamat-124, YashicaMat-124G Minolta Autocord

Bayonet 2
Also known as: Bay II
Outer measurement: 41mm
Inside diameter: 34mm
Sometimes marked: 34 or 36mm
Fits: Rolleiflex (with f/3.5 Xenotar and f/3.5 Planar)

Bayonet 3
Also known as: Bay III
Outer measurement: 46mm
Inside diameter: 38mm
Sometimes marked 38mm
Fits: Rolleiflex (with f/2.8 Xenotar or Planar)

Hope this helps clear things up…and if you know different i’m sure you will let us know 🙂

At the time of writing PhotographyAttic has a range of filters for sale in these mounts
Hoya B30 Yellow K2
B30 Pale Green
B30 Pale yellow
B30 Yellow
B30 Yellow Green
Bay II Skylight
Bayonet III Yellow Green
Aico B30 +2 close up lens set
Aico B30 +2 close up lens
Astron Aico B30 +2 close up lens set
Rollei Rolleinar Lens Set 2 28.5mm
Photax B-30 Close up no 3
Unbranded B-30 Close up no 3

You can also buy a Cokin adaptor and use A-series filters. We have the Cokin A to Rollei Bayonet II adaptor here

Why Hoyarex filters are often scratched

The Hoyarex filter system was really good: high quality filters.. Great variety of options in the range. Some glass filters. Solid holder. And a really useful rubber hood. But the Hoyarex System had a big flaw! And that has become evident over the years as more and more filters become scratched.
scratched Hoyarex filter
It’s not due to use either! These scratches occur when the filters are stored in their plastic case. The resin filter catches the edge of the case, which usually bends a bit in the middle. So after being jostled around in a camera bag the rubbing effect causes the resin to mark or scratch. Hoyarex filter case scuffs filter

So here’s a tip to prevent further wear. Buy a packet of lens tissues and wrap one over the filter at the top end that sticks out of the case. Then the filter wont get rubbed. You can use toilet tissue, but a lens tissue is softer and has no fibres that will come off and cause dust problems. tissue placed in Hoyarex filter case

View the entire range of Hoyarex filters here

Hoyarex Skylight 1B filter

The Hoyarex Skylight 1B filter – cat number 011 – is one of the most valuable filters in the Hoyarex range, yet is often overlooked, because its not a special effect filter.
Hoyarex Skylight 1B filter
But this underused filter will do two things to ensure your photography improves.

Firstly, and most importantly, the filter is a lens protector. The Hoyarex system is made so that when a filter is placed in the back slot it removes any possibility of dust reaching the lens. So if the holder is left on with a filter inserted the lens wont get dust falling on the surface or scratches. The skylight is the obvious choice as it has no special effect value. It’s also one of the few filters in the Hoyarex range that’s made from glass so optically very good.
Hoyarex filter in to Holder
But the filter has another use. A skylight filter has a very slight pink tint that has a warming effect when shooting in hazy days, so landscapes can be photographed with slightly more clarity. skylight filter pink tint

Using the filter in the back slot near the lens means there still another slot free for a special effect filter when you want to add a graduated effect, sepia tone or spot for example.  Hoyarex holder screwed on lens  Photographyattic has the Hoyarex 011 Skylight 1B glass filter for sale here

Understanding Filter Factors

A filter factor is highlighted on many filters as a multiple (or x). It’s simply the amount you need to increase the exposure by to compensate for light absorbed by the particular filter being used.

x2 is a one stop increase
x4 is two stops
x8 is three stops
x16 is four stops

If, for example, you have a x4 orange filter on the lens, the exposure has to be increased by four times – that is two full f/stops or shutter speed increments.

Lets say you have an exposure of f/5.6 (aperture) and 1/125sec (shutter speed) and add the x4 filter. You would either have to adjust the aperture two stops to f/2.8 or the shutter speed two stops to 1/30sec or both one stop so the exposure would be f/4 at 1/60sec.

Fortunately with modern through-the-lens (TTL) metering and automatic cameras the filter factor is taken care of, but you need to make the necessary adjustments when using manual cameras or manual exposure with flash.

To make things a little more complicated, some filters, such as the polariser, have variable exposure factors as you rotate the filter, and others have incremental factors such as 1.3x which makes it hard to adjust if you have an older camera with only full stop increments.

UV Filter Guide

UV Filter
The Multi-purpose UV is similar to the skylight, absorbing the ultraviolet rays which often make scenic shots hazy and indistinct. Moreover, the UV, especially when used with black & white film, increases contrast, reduces haze and generally improves the “sharpness” of your photographs

Many photographers buy a UV filter for each lens and leave them screwed on to protect the lenses’ front elements.

UV filters are available in round type that screw into the lens in ever size imaginable.

UV Filters available here

They were also made by Hoyarex for their square filter system.

Links to buy
Hoyarex 021 Filter

What is a Neutral Density filter?

The Neutral Density (ND) filter is one of the more useful filters you could include in your collection. Digital image processing can do many things but it can’t reduce the light reaching the film or CCD. That’s the job of the camera’s exposure system and an ND filter throws in a helping hand.

Neutral Density Filter

The name explains its purpose. It’s neutral (in colour) and it has a density (level of opaqueness).

Neutral Density filters come in a range of densities. The basic ND2 has a 2x exposure factor (or one f/stop) and an ND4 has 4x (two f/stops). There’s also an ND8 (8x or three f/stops) and a less common ND64 (64x or six stops).  You can go even further with specialist ND filters such as the Big Stopper from Lee Filters. This one has ten stops light reduction. So a shutter speed of 1/30sec would need to be increased to 30 seconds!

The filter goes over the lens and reduces the light reaching the film by the exposure factor of the filter.

If, for example, you had an exposure of  1/125sec at f/11 and you added an ND8, the shutter speed would reduce to 1/15sec or the aperture would need to be opened to f/4.

The reason to use an ND filter suddenly become obvious. If you want to force a slow shutter speed, for motion blur, or you want the lens at the widest aperture, for shallow depth-of-field, the ND filter can help.

It can also be used in combination with a flash to effectively reduce the guide number for close range photography.

The ND2 is hardly worth bothering with so we’d suggest you’re first ND filter be a ND4.

And another interesting type is the variable ND, like the one illustrated above. These are variable in strength, but, as reviewers have found, tend to cause criss-cross patterned illumination at stronger settings.

What are Wratten filters?

Wratten is a brand name from Kodak used for their series of coloured gelatin correction and conversion filters.

Kodak wratten filters

There’s a wide range – each one identified by its Wratten number.

The filters are very thin so are optically very good, but can be easily damaged

Wratten filters can be held or taped in front of the lens (or flash). Alternatively you can buy a gelatine filter holder for most filter systems for a neater way to attach the filter to the lens. Example include the Hoyarex Gelatine Filter holder and the Cokin P-Series Gelatine Filter Holder

They are also used in the darkroom for colour printing using an enlarger with a filter drawer. Cyan, Magenta and Yellow are available in increments of 5CC. Owners of the Bowens Illumitran and other similar professional slide copiers can use the filters to correct colour casts when copying from one film to another.

Photographers can tape a wratten filter over their flash and have a cancelling one on the lens so anything illuminated by flash will be the correct colour while the background will be the colour introduced by the filter over the lens.

10 essential photography filters

Optical camera filters

The top ten filters you should own will obviously vary from person to person and is dependent on the subjects you photograph. Our choice is most definitely the following:

  1. Circular Polariser (glare reduction and colour saturation)
    Great for landscapes, still lifes and architectural photography
  2. Grey Grad 4x (balance sky brightness)
    Great for landscapes
  3. Skylight (protects lens)
    All purpose photography
  4. Neutral Density x4 (reduces overall exposure)
    All purpose photography
  5. 81A (warms up skin tones)
    Perfect for portraits but also useful for landscapes
  6. Close up +4 (for the macro shots)
    Ideal for nature also good for still lifes
  7. Grey Grad 2x (a weaker variation on 2)
    Great for landscapes
  8. Neutral Density x8 (a stronger variation on 4)
    All purpose photography but idea for blurry  waterfalls
  9. Softar style diffuser (best softener for when you cant be bothered doing it in Photoshop)
    Perfect for wedding and portraits
  10. Star 8 (Adds star burst)
    Great for jewellery, also interesting for landscapes

Good selection? Let us know your favourite filters and what you use them for

Load of camera filters for sale

Skylight filter – any good?

The Skylight filter has been around for decades and is one of the most popular filters. It has a slight pink tint which is used to reduce blue haze in colour photography.

When taking colour photographs in bright sunlight, especially by the sea or in the mountains, ultra-violet rays and the brightness of the sky throw out the picture’s overall colour balance.

Removing any excess bluish tone, improves the overall clarity of the photograph. They also keeps skin tones free of colour reflections from nearby objects such as tree shade. With older film cameras this was very important as it helped restore the film’s natural colour balance. It’s less of an issue with digital as colour casts can be eliminated quite easily in post processing using an image editing program.

The skylight filter has a slight pink tint

The Skylight filter does not affect exposure, so some photographers screw one on the front of each of their lenses as protection for the front element.

There are some photographers who counter this action, suggesting that the filter will degrade quality. And it’s true if you put on a cheapy plastic option, but adding a high quality Japanese multi-coated filter will give minimal degradation to the image.  Any change will certainly not be noticeable to the naked eye.  And the advantage of having a skylight filter (or UV)  is you maintain a clean lens which would cost much more to replace than a scratched filter.

If you use a skylight filter you can keep it attached all the time, but be careful if you add other filters as the extended depth could cause vignetting on wide angle lenses.  Some manufacturers such as Hoya make slim versions to prevent this.

Skylight filters are available in two strengths 1A and 1B, the latter being a slightly stronger pink colour.

Skylight filters are available in round type that screw into the lens in ever size imaginable.
Round screw in filters available here

They are also made by Cokin for the square filter system in A and P sizes, and Hoyarex and the likes used to make them for their systems.
Hoyarex 011 Filter
Cokin A230