Hi folks,

To pass some time I’ve been doing some more tests with my K&F concept ND filters, long exposures, noise reduction, my intervalometer and custom white balance. I was keen to see what happened colour cast and image quality wise when I stacked two of my filters, my ND1000 and my ND8-128 set at ND8 giving a total exposure lengthening of 13 stops (10+3). I first set the custom white balance with my 18% grey card and took one shot at 1/15 sec. @ f/3.5 with single autofocus for reference . I then fitted the filters with the custom white balance selected and took a 9 minute 6 seconds exposure with the camera in bulb mode and with the camera’s noise reduction enabled. As previous both shots were taken under identical lighting and at the same aperture and focal length. Note, one cannot set CWB with a 10 stop or greater ND filter fitted as it’s just too dark thus I left it set with the no filter CWB setting.

I think that the shot with the filters fitted is a tad more saturated but it’s extremely marginal and it’s most definitely worth enabling the noise reduction if it’s not already set to on or auto. The downside is that it more or less doubles the length of the shot as it takes a dark slide so I had to wait nearly 20 minutes to view the resulting image. As an additional experiment I repeated this with noise reduction turned off but the result was pretty poor. Enabling noise reduction doesn’t present me with any issues as, given my interests, I’m unlikely to take many extreme long exposure shots.

Custom white balance and no filter for reference.

Same custom white balance setting with ND1000 and variable ND8-128 set at ND8.

Kind regards

Leigh

Hi everyone,

I did some tests this morning using custom white balance (CWB) with my various K&F concept ND filters. These were all conducted at the same aperture and ISO and under identical lighting conditions using an 18% grey card to set white balance without any filters fitted and each time I fitted a different filter. I was particularly interested to see if there was a shift of colour cast at each of the variable ND filter settings.

First a CWB shot taken without any filter for reference.

Now with the variable ND 8-128 filter @ ND8, ND16, ND32, ND64 and ND128. Custom white balance taken at ND8 setting and applied throughout.

Now the ND2-32 variable + CPL filter set at ND2, ND4, ND8, ND 16 and ND32 with no changes made to the CPL. Custom white balance taken at ND2 setting and applied throughout.

Lastly the ND1000 filter which is underexposed. I manually focussed before fitting the filter as it was too dark for the autofocus to lock.

With 1 stop exposure correction

With 1.5 stops exposure correction

I’m quite happy with these tests, the variable filters seem to be pretty consistent in terms of any colour casts across their setting range. There are some fairly minor changes to exposure/saturation but nothing that I can’t live with and one can set a custom white balance for each filter. I’ll happily use auto white balance all the time with the exception of when I have an ND filter fitted. Another thing I was looking for was if there was any noticeable decrease in sharpness and, if it is there, I think that it is minimal to say the very least, I can’t see it.

I should just add that this isn’t in any way a criticism of their filters, I’m happy with them and, in my opinion, they’re good quality filters at a fair price and there are far more expensive makes out there that also exhibit a colour cast. The important thing is finding a reliable method to correct for it, in the field when there’s not anything white in the frame that can be used to sample white balance in post processing..

Kind regards

Leigh

Hi everyone,

My first attempt at a video featuring some of my favourite photographic gear and gadgets which I hope you might find of interest. The cable release takes two AAA batteries which is handy, I’m using re-chargeable batteries in it. The Neewer tripod also has 360 degrees marking around the ball head to aid panoramic work and a spirit level. One can download the GPS log files from the Holux data logger to the computer via the USB port and use software such as Geosetter plus Exiftool (both free) to add GPS information to one’s RAW files. It can also act as a mock GPS provider using the built in bluetooth connection to a mobile phone.

Kind regards

Leigh