ND Filters and lens

Merlin5

Merlin5

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Hi guys. I've been reading an article about photographing tall buildings. It says to get dramatic clouds or to blur them, you need longer exposure, but that during daytime it's difficult not to over expose and blow out highlights. And so it said an ND filter is needed. The article goes on to say "We used an ND400 filter, which blocks out nine full stops of light. Once the filter is attached, you need to decrease the shutter speed until the exposure level indicator lines up with zero on the exposure scale." So, for my Canon nifty fifty, I'd need a 49mm filter. Do you recommend I get a 400 or some other number and any particular not too expensive one to get? Also, my Tamron lens would need a 62mm filter. At present, the only filter I have a is a Hoya Pro 1 circular polariser for the 50mm lens. But that isn't enough I guess for longer exposures.

The other question is this. I shot a photo yesterday of a very tall telecommunications tower with my 50mm lens. I stood right next to it and pointing up to the top of the structure getting some sky into the frame too at f/8. The photo came out nice and sharp along with blue sky and nice white clouds. But I could only get roughly the top half of the tower into the frame. I've been considering investing in a Tamron 17-35mm wide angle lens for general purpose landscape. But would a wide angle lens make any difference in how much of a tall structure can be captured if you're standing below it and shooting upwards? I'm guessing not because wide angled lens is presumably only for capturing more area left to right?
 
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So to answer what I think your questions are: yes, a neutral density filter will allow you to reduce your shutter speed to values that will blur clouds during the day. As clouds move fairly slowly you’d need a strong ND filter such as a 10 stop allowing 30 second to 1 minute exposures or there abouts depending on how bright a day it is. The process of using these very dark filters is a bit awkward though; they are too dark for the camera to see through so you have to shoot in manual. I put the camera on aperture priority mode and set the aperture I want e.g. f/8 then make a note of the shutter speed. Switch to manual and then decrease the shutter speed by 10 stops (most cameras have shutter speed stops in 1/3 stops so I count ‘111, 222, 333, 444 etc. up to 10). You also need to focus before putting the filter on - so that your camera doesn’t try to refocus when you take the shot you need to either back button focus (google it) or manual focus by zooming in on live view (Maybe google that too). If the shutter speed is longer than 30 seconds you will need a remote shutter release and use it in bulb mode. Finally, you will need to block any light getting into the viewfinder for the duration of the exposure or you’ll end up with weird lines. [PLEASE DON'T TRY TO BYPASS THE SWEAR FILTER], that sounds complicated when it’s written down!! Alternatively, to save money you could take multiple exposures and blend them in photoshop or alternative (stack them and use average blend mode - google that too!).

A wide angle lens will increase the field of view at the top and the bottom of the frame so getting a wider angle lens would help you get the top of your tower in.

i hope this helped - even if it convinced you not to bother with long exposures just yet! They’re very fun to do and create some very impressive images though so it’s something you should consider at some point!
 
Hi Tom and thanks! Lol yes, a little complicated! :D I've got the gist but need some clarification.
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"I put the camera on aperture priority mode and set the aperture I want e.g. f/8 then make a note of the shutter speed."

So at this point, I still don't need to press to focus, just see what the shutter speed is, have I understood that right?

"Switch to manual and then decrease the shutter speed by 10 stops (most cameras have shutter speed stops in 1/3 stops so I count ‘111, 222, 333, 444 etc. up to 10). You also need to focus before putting the filter on - so that your camera doesn’t try to refocus when you take the shot you need to either back button focus.. "

Yeah, I use back button focus.
So before focusing, switch to manual mode, decrease the shutter speed by 10 stops, then use back button to set focus, and then put the filter on, have I understood that right? And once the filter goes on after having focused, should I be seeing the exposure meter in the centre at 0 and if not, adjust the amount of shutter speed stops?

I think I'd prefer to rely on the autofocus so probably wouldn't do it with manual focus in liveview. I've not really used liveview much, don't know if you'd recommend it over auto focusing through the viewfinder?

What's a good way to block light getting into the viewfinder, put a piece of electrical tape over it? And that would still apply even using liveview I presume?

Thank you for also answering my question about a wide angle lens.
 
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It doesn’t matter when you focus really - as long it’s before you stick the filter on. And you can ignore the exposure meter - if it’s properly exposed before the filter goes on and it’s 10 stops over after the filter goes on it will be good. Unless the light chages! Which it often does on long exposures... I just hold something dark next to the VF. Doesn’t have to be light-right, just need to stop direct light getting through.
 
Thanks Tom. Would you or someone be able to recommend a 10 stop ND filter to buy? What about ISO, set it to auto?
 
Absolutely don’t set set iso to auto otherwise it will ramp the iso up as soon as the filter is attached. Keep it as low as possible.
I’d highly recommend getting a slot in filter system as opposed to a screw in one, as it becomes incredibly tedious keep unscrewing it every time you re frame a shot or refocus.

Also with screw in filters you drastically increase the chance of screwing the focus up if the front of the lens rotates or moves when focusing . Most modern lenses don’t tend to now, so it makes life a little easier, but cheaper and older lenses do and it’s a right pain.
 
TCR4x4 said:
Absolutely don’t set set iso to auto otherwise it will ramp the iso up as soon as the filter is attached. Keep it as low as possible.
I’d highly recommend getting a slot in filter system as opposed to a screw in one, as it becomes incredibly tedious keep unscrewing it every time you re frame a shot or refocus.

Also with screw in filters you drastically increase the chance of screwing the focus up if the front of the lens rotates or moves when focusing . Most modern lenses don’t tend to now, so it makes life a little easier, but cheaper and older lenses do and it’s a right pain.
Click to expand...

Thanks for the advice. I don't know anything about a slot in filter system or where it slots in. What am I looking for, ND 10 stop slot in filter?
 
You’ll need a 100mm filter holder, adapter to screw into the lens and the filter.
Loads of different holders about, main are Lee, hitech, Nisi and kase.

Take your pick really. Same for the filter. I’ve used Lee big stoppers and hitech firecrest 10 stoppers.

I now use the Kase K9 holder with the magnetic polariser. You can slip the nd in behind so you get the long exposure and the polariser Effect for far far less than the equivalent Lee setup.
The Kase holder with the polariser is about £110, you then just need the ND filter and the correct size adapter to screw into the filter thread of your lens
 
Thanks TCR4x4. Now that you've prepped me on what to get, I'll look on youtube to actually see how all these components look and fit together.


What does the magnetic polariser do, is that for the same effect that my circular polariser gives?
 
Yes, it’s just the way it mounts.. magnetically. Makes it easier to remove And a lot thinner. You spin it via a small wheel on the holder.
I did a pretty low rent video many years ago on the lee system And a 10 stopper. You can see how it looks and works to a degree on that.
You may notice they way I calculate the exposure is a bit odd... yes it is, that’s just me.

View: https://youtu.be/GrUWVAHli08
 
Thanks, I'll check out your video! One other question if you don't mind. I've not really used my circular polariser yet. Before I bought it, I watched some videos where people said that polarisers only work if the sun is coming in at 90 degrees from where you're standing, i.e, hitting the left or right side of you. Something like that anyway, I could have got that wrong. Is that true though?

edit: Just started watching your video. You look like a bass player I work with. :)
 
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It’s most effective at those angles but can be used at others. Easiest way is look through the viewfinder at your reflective subject and spin it. You’ll see it working or not.
 
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