Ironically, for someone who once wrote about the need to label things to help my understanding I don’t like to label myself photographically. I am just a photographer. If pushed very hard however I would probably own to being a landscape photographer. As a landscape photographer I understand the need to balance the tonal ranges between, for example, sky and land. There are various ways but being rather old school my preferred, but not my sole, approach is graduated neutral density filters, ND Grads for short.
It wasn’t a big surprise then that now I have the basics of this drone photography lark under my belt my thoughts should turn to the subject of how to control tonal range in my drone images. I’ve tried the exposure-bracketing feature on the drone which works reasonably well but there is still that hankering to get it right “in-camera”. So I started to think about and look out for ND Grads for my Mavic Pro. Unlike a tripod-based DSLR I cannot change filters mid-flight with the drone; it has to be brought down, landed and powered off in order to attach or swap out a filter. In addition, owing to the size and build of the drone lens it is not possible to vary the positioning of the graduation – just as with a screw-in filter for your traditional camera the position of the graduation is a given. So, using filters on the drone has to be a considered option.
Whilst looking on the internet I found a third party set of three different ND grads (grey, blue, orange) for £40. I found no review for them online, apart from amazon.com reviews which I rarely trust these days, however reviews of the company’s ND and polariser filters elsewhere on the ‘net were reasonably positive so I marked them as a “maybe”.
I then found a set by Chinese company Neewer for just £11. I’ve used Neewer products before and found them reliable rather than spectacular so figured I’d chance my £11 on a set which duly arrived the following day from that well-known international online retailer beginning with A. But how did they fare?
I put the drone in the air with no filter attached then brought it back down to fit the ND grey filter. This is best done with the drone powered off and the gimbal lock in place. I then returned the drone to the air and endeavoured to take exactly the same image (I didn’t do too bad) to use as a comparison. Back home I converted both RAW (DNG) files in Adobe Camera Raw applying the same basic adjustments. The results are shown in segments 1 and 3 above. There is a noticeable grey cast in the image taken with the filter attached but this was easily removed as can be seen in segment 2 and I was left with a well-balanced shot.
But does the filter make a lot of difference? As can be seen above the filter definitely darkened the sky but looking closely at the image and the bottom half of the frame does appear a little bit darker too. To test this I left the filter on and took a third image, with no sky to see what happened.
I was expecting the top half to be darker than the lower half but that doesn’t seem to be the case. I took several other test shots too and came to the conclusion that the filter was having minimal effect on the image in terms of changing tonal range.
The blue graduated filter did definitely add a blueish tint to the upper half of the frame but again did very little beyond this to darken the tones in the sky relative to the lower half of the frame.
So, you get what you pay for in life I guess and for me based on this mornings experience these filters do not function as well as they might especially in terms of their prime purpose – that of reducing the tonal range in the image. However, I will try them out on another day when the sun is shining brightly and the tonal range is larger to see if it was the light not playing nicely this morning.
Will I be trying the £40 set? I’m not sure yet – I think I need to do some more research and see what other peoples experiences have been (assuming I can filter out the dubious “paid for” reviews on amazon). The lens of the Mavic is very small however and I’m starting to think that there just isn’t enough real estate to allow the graduation to work as I’d like.
The jury is out as they say and I need to investigate further before parting with any more money!