Tips for using a CPL effectively

Some of you who follow our work would know that a circular polariser (CPL) lives on the front of our lenses. Recently, we’ve made a change to using Nisi filters which means that for the most part, we use the kit CPL included with their variety of holders. As with many phases of development in photography, using a CPL is one of those subjects where once you discover it, there’s an initial trend to blindly use it no matter the situation! (Didn’t we all go through that to some degree with ‘HDR’ ??) With time and experience though, one becomes a little more judicious and refined with its use. I would say that a CPL is used for the majority of our images and I thought I’d share some do’s and don’ts about their use.

What does a CPL do?

  • Cuts out reflections : particularly useful for forest scenes.
  • Deepens natural colours : useful for most scenes.
  • Acts as a very light ND filter (1-1.5 stops): useful for seascapes in bright light.
  • They are potential rainbow killers! Be wary of having a CPL on with wide angled lenses if you think a rainbow is even a possibility.
  • It’s also another piece of glass that could interfere with image quality , particularly in moist situations and prolonged shooting. If I had to choose between polarisation for colours and a clean image, I would choose a clean image and remove the CPL.

Predawn light: A situation where I would be trying to avoid using a CPL since it acts as a light ND filter. For this scene, I was at iso 800 and did not want a shutter speed longer than 5-10 seconds or all texture would be lost. Hence I removed the CPL.

 

It’s generally a good idea to remove all filters (CPL included) when shooting for a sunstar.

 

Mornings with rain and breaking light lead me to prepare for a quick CPL removal ! If positioned incorrectly, a CPL may well polarise out the rainbow entirely or at least in part.

What do you do with the dial?

  • Its maximal effect is perpendicular to light source. If you point your index finger to the light source and poke your thumb out perpendicularly, the maximal polarisation occurs in the plane as you rotate your hand around.
  • If  your CPL has a dot on it, point that to the light source for maximal effect but use judgement depending on the presence of plain skies in particular.
  • Don’t forget to turn the CPL if you happen to change from landscape to portrait orientation (or vice versa) otherwise one of your images will have no polarisation effects!

In a forest situation, the light source is generally from up above. A useful starting point to achieve maximum polarisation is to have the ‘dot’ of your CPL pointing straight up in whatever orientation you are shooting. If your CPL does not have a ‘dot’ to indicate maximum polarisation direction, you may need to experiment for the best result.

Forest/waterfall scenes:

  • Use it to deepen the greens and allow a ‘see through’ effect to river beds.
  • Point the ‘dot’ on the CPL up to the sky.
  • Remove it if needing to keep foliage still with faster shutter, or alternatively, take separate frames with the CPL on at higher iso /larger aperture to allow adequate exposure at the desired shutter speed.
  • And remember (again), turn that CPL if you change orientation!

A forest scene with the CPL positioned to have minimal polarisation (dot sideways). Note the glare of the foliage and the presence of a waterfall reflection. The greens are also less vibrant.

The same scene with the CPL ‘dot’ turned upward. Note the vibrance of the greens and the removal of the waterfall reflection and see through effect to the creek bed.

Sometimes, to get the best of both worlds , polarised and unpolarised images can be blended such as in this example where the reflection is maintained along with the vibrant greens.

A perfect scenario for a CPL is a cloudy day with alpine streams of various natural hues. The CPL can really enhance the hues of the water while having no banding in plain skies to worry about!

Open skies:

  • Very good with long focal lengths to isolate your subject with blue skies.
  • Avoid using with wide angled images especially when perpendicular to light source (or expect to have to correct in post process) .
  • Use it to enhance detail in clouds : be wary of patches of open sky in the clouds themselves.
  • When in doubt with open skies, take the CPL off. It can be quite tricky to blend images with polarised and unpolarised images.

Enhanced clouds but note the darkened band in the blue sky perpendicular to the light source to the right of the image.

The sky is unpolarised in this version of the same scene but note that the reflections from the water have been removed by polarisation in a different plane.

RAW file of a wide angled image demonstrating the problematic band that a CPL can cause when shooting perpendicular to the light source.

The same scene as above but shot at a longer focal length. If your subject is perpendicular to a light source, shooting at longer focal length with the CPL turned to the light really can enhance the subject greatly without the same problematic banding that is seen with shorter focal lengths.

Not that this sky needed it, but the CPL certainly helps bring out textures in clouds.

Seascapes:

  • Can enhance natural colours and reduce glare off rocks.
  • Sometimes the glare or reflection shooting into sun is required/desired therefore you may not want to use the CPL.
  • Sometimes in bright light, you may be using the CPL purely as a light ND filter in order to achieve 0.3-0.5 second exposures in bright light.

Generally speaking, polarisation isn’t necessary when shooting seascapes directly into a light source, especially when shooting for sunstars.

 

A CPL in this situation may slightly enhance general colours but may also reduce colourful reflections. In any given situation, it may help you achieve a slightly lower shutter speed rather than stopping down to small apertures such as F22.

Conclusions:

  • I consider a CPL a very important part of a landscape photographer’s kit.
  • If your CPL does not have a ‘dot’ I would experiment and perhaps even mark out where the ‘dot’ for maximum polarisation should be as a time saver.
  • Forest scenes are where they truly allow colours to sing .
  • Beware situations where you would rather not use one : plain skies, sunstars, rainbow opportunities and shutter dependent low light scenes
  • Most importantly, you need to decide according to your shooting style and preferred subjects whether you invest in one. Lastly, if you do invest in one, consider using screw-on filters for shooting handheld. For tripod situations using a filter holder, I would recommend using the NiSi filter holder system which has the CPL as part of the holder itself (take this with a grain of salt as I am an Australian Nisi ambassador !)

Happy shooting all and I hope there was at least one bit of information there that was useful! We’re off the New Zealand 🙂

 

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Sunshine in winter

For the last two years now, we’ve headed up to Queensland to escape the Adelaide winter (not that it’s that severe). Each time, we’ve been blessed with variable conditions. This year’s trip was an extended family trip to the Sunshine Coast where we were based in Tewantin. This made it a great base to explore Noosa Heads National Park in particular. I’ll explain the rationale behind some of the images from each location.

Day 1: Morning at Dolphin Rock.

The reason I wanted to visit this location was due to its influence on my early photographic ‘career’. I had seen numerous images of this rock at Point Cartwright by flickr contacts and wanted to see it for myself. Given how short our trip was, I had no option to plan appropriate tides so I really had to deal with what I was given. Thanks to rough directions from Brisbane photographer Martin Canning, I was able to find the rock very quickly after parking the car at the nearby lighthouse car park. The timelapse below shows an advancing tide with the evolution of light. My aim was to capture dynamic motion flowing over the rocks and eventually, to capture a sunstar image based on the ‘tip’ of the dolphin’s nose. I managed to catch up with long time flickr friend Adam Randell here as well.

Sunstar over Dolphin Rock at Point Cartwright

Day 1: Raining light at Noosa heads

On our first evening, we walked to the first cove along the coastal trail at Noosa Heads national park. While we were exploring the area looking for crabs and other wildlife with the kids, I spotted a group of rocks which I thought might light up well at sunset. As a downpour occurred which sent the rest of the family running for cover, the area was lit in a haze of orange and gold which I tried to capture with my hastily scouted foreground elements.  Due to the rain, I shot most of these images without filters and gave the kim wipes a great workout to keep the shots clean! Unfortunately, this was the last shoot with my Sony A7r2 as I fell in the water with it 😦 . I met Stephen Waller by chance here as well .

Light breaking through rain and clouds

The last series of shots before camera death!

Day 2: Smooth Granite

On the following morning, I was on a bit of a downer as the camera had not managed to revive itself overnight. Nonetheless, I did bring two bodies on this trip (1 for timelapses). My goal for this particular morning was to scout the coastline along the northern shores of the national park. The tide was high which restricted many opportunities but I settled for photographing the smooth granite boulders at the appropriately named Granite Bay. There wasn’t much light on offer due to thick bank of cloud on the horizon but an after dawn, the sun finally made its appearance. I wanted to capture a long exposure with accentuation of the foreground rock patterns leading toward the tall granite boulder. This was best achieved as wide as possible using the Laowa 12mm lens. I also wanted to capture golden light falling upon the rocks but during a long exposure, I would have been very limited by the huge dynamic range involved with attempting this as a single capture. I therefore blended the long exposure shot with a few shorter exposures for the light on the rocks taken without any filters on.

After I had finished shooting at Granite Bay, I did some scouting for potential evening shoot locations. I decided to take some travel oriented shots of the many surfers at Tea Tree Bay enjoying the beautiful winter sunshine.

A blend of several long and short exposures to accentuate the smooth textures and light. Long exposure taken with 10 stop ND filter.

Image with ND filter on the left for smooth skies and water. Image without filters on the right for the light on the rocks

Tea Tree Bay in the early morning

Day 2: Suburban Forests at Buderim

During the day, we took the kids for an easy rainforest walk to the base of the waterfalls at Buderim . We found it remarkable that such lush scenery could be in very close proximity to surburbia. There had not been much rain in the preceding week, hence the waterfall was barely flowing. I noticed light falling upon a fern in front of the waterfall and set out to photograph the scene with the fern framing the waterfall. It was quite difficult to obtain this perspective and I ended up having to take my ballhead off the tripod and wedge it on to a rock to keep it steady while taking these 0.3 to 0.5 second exposures. The morning made for a great family outing with relatively easy access. Thereafter, the kids had fun at the Ginger factory before we returned home for Jaime’s (our 3 year old) nap.

Serenity Falls at Buderim Forest.

A video of the girls fun activities in Noosa.

Day 2: Reflections from Tea Tree Bay

This set of rock pools caught my eye as I was walking back from the morning shoot, so I had an easy destination to head toward in the evening. It was fortunate that I had scouted the position earlier in the day as I nearly missed sunset due to the parking madness at the National Park on a Sunday evening. Fortunately , after stalking some departing surfers, I was able to find a park and dash off to Tea Tree Bay. For the earlier image (middle) I had set up to photograph a focus stack with foreground rock and sky frames. While waiting for the light to evolve however, I found more appealing shapes in the same area and photographed those instead. Unfortunately, in the rush of moving around, I did not focus stack so there are some soft elements to the very immediate foreground.

Portraits of the light at Tea Tree Bay

Day 3: Paradise undiscovered

This was to be my last morning of shooting on the trip. I had read about some caves along the Eastern Beaches but knew it might be a little dicey to reach them since I had not scouted the area and would be approaching in the dark. After a couple of false trails leading to cliff faces, I found my way down to the shoreline north of Alexandra Beach and looked around in the dark for the caves. It turns out that one of my false trails in the dark was actually the right trail ! Next time i’ll know where to go to get into the caves proper but for this particular morning, I kept the shoot relatively dry and watched as a grey dawn turn gold yet again once the sun peeked through. All in all, it was a great short break which I found very refreshing since Noosa is a much more relaxed part of the world than the Gold Coast. In between family outings, most of the coastal locations were relatively to access with lots of different possibilities at dawn and dusk. Hopefully , we will return in the future!

The waves can really crash hard at this location – I chose to play it safe having already lost one body for the trip.

Long exposure panorama of the churning coastline at Paradise Caves (to the left of frame)

A Wow for Laowa?

In the last month or so, I’ve had the opportunity to use Laowa’s 12mm F2.8 zero distortion lens along with its own filter holder and Nisi’s custom made filter holder. The version I have is for a canon mount. Overall, it’s a great piece of equipment for a reasonable price and takes up very little real estate in an already fully stuffed camera bag. Like most gear however, it’s not without its issues. I’ve only taken it out for three shoots and used it around the house, so there may be aspects that I haven’t had the chance to test entirely but I’m more than happy to test any aspect requested (if I get the chance to shoot!)

Unfortunately I’m not really tech-savvy when it comes to lens reviews, I just want to know how it serves my specific purposes. With that in mind, this is a rough index of what I’m going to comment upon.

  1. The lens itself
  2. How wide is 12mm ? Is it too wide?
  3. Night photography
  4. Sharpness stopped down
  5. Flare and sunstars
  6. Filter holders (native and Nisi)

The lens:

I’m not going to bother with discussing things like packaging. It’s sufficient and professional . What surprised me out of the box was how compact this unit is. It weight (610g) would allow me to bring it on hikes though perhaps only those where astro photography is a priority. It feels solid in the hand and appears to be built like a tank. Its size also allows a huge bonus for a lens of this focal length ; the ability to use 100mm filter kits! As a prime lens with manual focus, it would be difficult to achieve quick ‘on the fly’ shots without risking focus issues. Having said that, because it’s a prime lens, it has a nice feature of charting hyperfocal length on the lens itself .  You can hence position focus at infinity at one end , and make sure there are no objects closer than the focal length marked at the other end of the scale for your given aperture (see diagram below). I have yet to shoot panoramas with this lens but there is a marked ‘entrance pupil’ on the lens that assists with finding a nodal point .

The lens with its bulbous front element.

The rightmost number indicates the current aperture. The middle row of numbers indicates that focus at F5.6 will be between approximately 0.45 to 0.7m. If you wanted to use this as a walkabout lens without thinking, you could adjust the leftmost marker to infinity and not shoot anything closer to the focal length indicated on the right marker

How wide is 12mm?

The answer is VERY wide. This is probably best shown with some images which I took at Lake Bonney. The first image was taken with my Canon 16-35mm F4 lens. The second image was taken with the Laowa albeit, standing a few metres further back. You can see the inclusion of the tree on the left. This makes for a lot of possibilities with sweeping foregrounds but could lead to minimising of anything that’s not very imposing in the background.

16mm shot taken at Lake Bonney

12mm showing the inclusion of the additional tree on the left but minimising of the furthermost trees as seen in the 16mm version

Swirling foregrounds for waterscapes become very interesting with the 12mm. Unfortunately, given I was standing in the water, I did not take a comparison shot with the 16-35mm

Night photography:

As an owner of the 16-35mm F4 lens , I was making do with F4 for night images so once again, the prospect of a wide angle F2.8 lens was extremely appealing. The other lens I was considering was the 16-35mm F2.8 III. My version II has taken a fair battering and I had always had issues with coma and softness in the corners which meant that I was willing to sacrifice one stop of light to use the 16-35mm F4. Finding focus in the dark has always been a little finicky but achievable. With this lens, as in the example illustrated above, I set the far focus for my aperture at infinity meaning that I could have everything in focus from approximately 1.5m and beyond. During this shoot, I did not check to see whether the infinity focus itself is true infinity. This technique worked quite well for me. The main issues I wanted to explore were a) how sharp is this lens at F2.8 at the centre and in the corners? b) how does this compare with the canon 16-35mm F4? c) Did the focusing method above result in ‘missed’ focus. The images below demonstrate the results. The Laowa is a little soft at the corners but still better than the 16-35mm F2.8 II. Centre sharpness was just fine . One interesting phenomenon not related to the lens itself was the ‘ole 500/focal length rule for still stars. At 12mm , I though I could therefore get away with 40 second exposures and have no trailing. For some reason, exposures of 30 seconds or more still showed significant trailing which means that rule doesn’t seem to apply for very wide focal lengths??

100% crops from the same image taken at F2.8 30 seconds. You can see some softness in the bottom image but not a great deal of coma.

Corners of the Laowa vs Canon 16-35mm F4. The Laowa was a 30 second exposure, the Canon 25 seconds.

Final edited image of the scene demonstrated in the first image. A second foreground exposure was taken at lower iso for cleaner noise in the dark water.

Sharpness at F11 and beyond 

Most of the time in the field, I’m shooting between F11 to F16 since I tend to shoot with foreground elements present. The images below show the centre vs corner sharpness at 100% viewing in LR of the RAW file (with shadows lifted so you can see the detail). They were taken within a minute of each other with the same lighting conditions.  I think there is very little between the Laowa and the Canon lens at the centre while there is some softness of the Laowa in the corner comparison. Note there wasn’t a lot of chromatic aberration even with this kind of dramatic lighting going on.

Not much difference in centre sharpness between the two lenses

Both are a little fuzzy in the extreme corners but canon seems a reasonably clear winner here?

Sunstars and Flare:

Stopped down to F22, I’ve had a couple of opportunities to shoot sunstars. The 7 aperture blades do seem to provide a good star but perhaps not as aesthetically pleasing as the Canon 16-35mm F4 ( and F2.8II). Shooting directly into light does give a circular flare which I’ll have to experiment with when there’s more direct sun.

Different types of flare evident between the Laowa and Canon lenses.

Laowa’s sunstar is quite appealing

Filter Holders:

 I received my lens with Laowa’s own filter holder. I had heard some horrendous stories about it so I was prepared for the worst. In actual fact, the current version I received was nowhere near as terrible as was made out to be. It clips directly on to the front of the lens and has slots for two 100mm filter and a 95mm polariser. I don’t own a 95mm CPL so this was an aspect of their filter holder that I could not test. It did cause vignetting but once again, not that troublesome as you can see from the images below. It’s main limitation (other than the 95mm CPL ) is the fact that ND filters with foam gaskets to prevent light leak just do not fit into the slots in the correct orientation. In an attempt to slot them in with the foam facing outward, you can see the somewhat amusing result below.

Nisi filters however do provide a custom adapter ring which also easily slots on to the front ring of the lens. It allows their standard CPL to be used as well as slots for 2 ND filters. I wanted to see how the three slot filter would perform and unfortunately , with three filter slots in place, even the Nisi holder does result equivalent vignetting as Laowa’s holder. Since I have two filter holders, I will have to remove one slot from one but I can see that for many shooters, having to remove one slot might limit options stacking when using other lenses and wanting to stack three filters. I will be using the Nisi version of the holder simply because this allows me to use a CPL and ND filters.

Vignetting of the Laowa holder with 2 slots vs Nisi holder with 3 slots

Attempted (and unsuccessful)  long exposure with the Laowa and a successful one with the Nisi holder

A) Laowa filter holder B) Nisi adapter ring attached C) Nisi holder with 3 slots attached D) Nisi with standard CPL

Conclusions

Overall, I think the Laowa 12mm F2.8 is a good quality lens but not quite at the standard of the better Canon L lenses. It’s good for photographers whose style leans toward expansive foregrounds and grand scenes. It’s also a very good lens for milkyway photography. It’s a solidly built lens that so far seems durable (I’ll have to comment on this a year down the line) and there are options for using 100mm filters which is pretty unique for a lens of this focal length. The Nisi filter holder is definitely the more practical of the two filter holders that are available. I don’t think I would bring this as a sole lens for a backpacking trip since it would be too wide for many documentary or detail scenes. For those used to shooting not quite so wide , it may take some time to get used to finding different styles of compositions.  For $1400 AUD, it’s less than half the RRP of the Canon 16-35mm F2.8 III and about the same price as the 16-35mm F4.

I’ll be honest in saying that before I received this lens,  I wouldn’t have gone out of my way to buy it.  But now that I have it, I do realise that it has opened up doors. I’ll pretty much use it exclusively for my milky way shoots and will definitely bring it for most other landscape shoots excluding the multiday backpacking trips. I hope that the images and information was helpful to you and for those of you who own it, I’d be interested to hear of your experiences! It’s a ‘wow’ to Laowa from me 🙂

Beautiful skies over Encounter Bay. Shot with a Nisi filter holder and 4 stop soft GND.