01-27-2018 11:18 AM
I would like to buy a ND filter (stop 10 I think) for trying long-time exposure.
I have a Canon EOS 100D and 3 lenses: EF 50mm f/1.8, EF-S 18-55 mm f/3.5-5.6 and EF-S 10-18 mm f/4.5-5.6. Of course, they all have different diameters... I don't have a massive budget but I prefer waiting rather than buying a bad quality filter.
At the same time, I am not experienced at all with long-time exposure and I might not be sure what I'm after so I don't really want to buy the most expensive filter to realise I don't want a 10-stop in the end but something else.
Do you have any suggestions? Shall I buy a filter with a specific diameter or is it better to have an adapter to use square filters?
I'm a bit lost!
01-27-2018 11:53 AM - edited 01-27-2018 12:27 PM
Typically, one would buy the filter size for your largest lens, then use step down rings for your smaller lenses. For example, I could have 82mm ND filter. I could use an 82mm to 77mm step down ring to use it on smaller lenses.
You do not want to use a smaller filter on larger lens, because you will get severe vignetting.
A 10 stop ND filter is pretty strong. What are you trying to photograph? Or, how long of an exposure? An ND filter is useful with a very wide aperture lens, on a bright sunny day.
01-27-2018 12:02 PM
Best idea is to get smaller intensity ND filters because you can combine several if needed. A typical ND is 3 stops. High quality ND's can run in the $100 dollar range. The B+W 58mm MRC Solid Neutral Density is a god choice and is around $70 bucks. (Fits your Canon 18-55mm f/3.5-5.6 IS STM Lens.)
01-27-2018 12:35 PM
You can buy a larger filter and then buy "step-up-rings" to adapt the filter to other lense thread sizes.
For example, most of my lenses have a 77mm filter thread diameter. But I do have a lens that usesa 67mm thread. Soooo... I picked up a 67-77mm "step up ring" (which probably ran me all of $15) and now I can use my 77mm filters on my 67mm lens.
The key to this is that the actually filter needs to be sized for your largest diameter lens (or the largest diameter you think you'd ever get). You wont find rings that go the other way (you can find 67-77mm rings, but not 77-67mm rings because that would result in extreme vignetting around the image.)
My 77mm filters (and 67-77mm step-up-ring) served me well... UNTIL I bought a couple of 82mm lenses.
An alternative is to buy square "slide in" filters and put a filter holder on the lens. Square filters come in a few sizes but the most standard/common is the 100mm width (4" width). The holders then use an adapter ring ... you buy the ring that matches the thread size for your lens. The holder has "slots" or "rails" on the front and you just slide the filter into a slot (usually they have a few slots allowing to stack filters.) The nice thing about the 100mm width filters is that they're bigger than every lens you would likely ever own -- which makes them universal. The adapter rings are cheap. So you buy one for each different filter size you have.
So now, in addition to my 77mm round thread-on filters, I also own 100mm width square "slide in" filters ... and the appropriate mounting rings. So now every lens I own is covered for everything I could possibly need with just the one set of square slide-in filters and I wont need to re-purchase filters regardless of future lens-buying decisions.
Cokin makes low-cost holders and filters.
Higher end filters are made buy companies like Lee Filters, Formatt Hi-Tech, or Singh-Ray. (these are not cheap). Most of the filters are a resin (and I do recommend resin) but a few are only available in glass. Polarizing filters require real glass (not resin). The reason is that real glass cap chip at the edges (so handle with care ... use a protective case.)
That works in general, but there's something particular about the 10 stop filter to be aware of.
I have 2 stop ND filters, 3 stop ND filters. While these do reduce the light ... there's still enough light coming through that the camera can easily meter & focus and you can also see to frame/compose your shot.
This is not true of a 10 stop ND filter. When you put that filter on, you only get about 1/1000ths of the light coming through. This means it will appear to be pretty much black when you try ot look through it. There will not be enough light for the auto-focus system to work nor will there be enough light for reliable metering and you'll quickly observe that you can't see to frame or compose the shot.
To use the 10-stop filter, you will need a tripod (this is basically "required" equipment when using such a filter), put the camera on the tripod and frame/compose & focus the shot without the filter. Now switch 'off' the auto-focus on the lens. You will probably want to use Manual exposure mode, but take a meter reading and dial in those exposure settings to the camera EXCEPT for the shutter speed. For the shutter speed you will manually work out 10 stops increase to shutter duration.
Now you can attach the filter and take the shot (knowing that you pre-composed, pre-focused (and disabled auto-focus), and pre-metered (and compensated the meter reading by 10 stops).
It's a bit more work to use a 10-stop filter.
01-27-2018 01:43 PM
Sound advices all around from the regular folks...Just a couple of things from my perspective...
1. I'd highly recommend getting a square holder system instead of the round stuff. The most common filter that would work for pretty much everything is the 100mm. This system tends to be more expensive but offer several advantages. One is that it's easier to install individual filter(s) - in case you need to stack them. Seems like a no big deal thing until you're in the field, in the dark in subzero temperature trying to screw in a round filter... and two is you can avoid some vignetting. This recommendation comes from a guy (me) who has tried both and ended up with the holder system...wasting lots of money in the process. You mentioned you want to buy it right and buy it once.
2. I echo the advice not to get the 10x ND from the get-go. I use the 3x and the 6x the most, sometimes together. Keep in mind that even for the best ND filters money can buy, you will get color changes and vignetting that will require post processing correction. The color change gets worse the darker the filter gets. So if you can use the 3x or the 6x and don't need the 10x don't use it as the effects get worse.
01-29-2018 06:11 AM
Thank you for all the good advice!
I am not fully sure if I want a 10 stop ND filter to be honest, 3 and 6 stops seems nice but I was reading that lots of people start with the 10 stops one - although this is strange considering it requires more skills from what you said and what I read on the net. I would like to take pictures of water and sunsets/sunrises with nice red skies. I am not sure how smooth I want the water to be and how to decide which filters would be necessary for what I'd like to achieve. I guess I need to try but I can't buy all kinds od ND filters. I have a Manfrotto tripod.
I was also reading that stacking them is not recommended so I am a bit confused.
Does having a adapter ring bring new problems in term of image quality?
At first, I thought it was better to buy square filters indeed so I don't have to worry about having different filters for different lenses. I don't know what my next lense purchase will be so I have to say I would prefer having a system which works for all.
Is it much more expensive though? I don't know what brands to look at or anything so it is very comfusing for me atm.
Silly question, how do you fit the holder to your camera? I am really a noob with long-time exposure and it is something I would like to work on in 2018!
Finally, how do you correct vignetting? I use Lightroom.