Table of Contents

Filter Type
ND filters and How Many Stops You need
- ND filter brands and naming

Filter Type

filter guide:
- all pro expensive one comparison: http://forum.xitek.com/thread-1008967-1-1-1.html

UV filter
Polarize filter
Closeup filter
ND filter
color filter
other filter
Black card
- black card technique as traditional way of Photoshop-like masking: http://hanjies.blogspot.sg/2009/10/black-card-photography-part-i.html

ND filters and How Many Stops You need

So when you consider a ND filter, there are mainly 2 purposes for it

reduce incoming light, and be able at using f1.4 like lens wide open, when you already hit lowest ISO, like 100, and also hit highest shutter speed, like 1/1000sec, to achieve Corret Exposure
reduce incoming light, and be able to use a extreme slow shutter speed like 10-20sec, after you already use f8 and ISO 100, to achieve Corret Exposure
or combination of both

Case Study

Situation 1: Bright Day Light and Wide Open portrait shot, (Ambient Light: EV 15)
- answer: at least 3 stop ND filter needed for this case.
- extra answer: if you doing flash fill, and you stuck with 1/125 sync shutter speed,then you need additional 4 stop ND to bring 1/2000 sec to 1/125, that is total 7 stop ND filter.
- extra extra answer: if you

case	F	Iso	Shutter	note
normal correct setting	f16	ISO100	1/125 sec
max wide open setting with 4 stop Pshift	f4	ISO100	1/2000 sec	f16→f11→f8→f5.6→f4 1/125→1/250→1/500→1/1000→1/2000
max wide open with addition 3 stop ND	f1.4	ISO100	1/2000 sec	f4→f2.8→f2→f1.4
	f2.8	ISO100	1/500 sec	for f2.8 lens
stuck with 1/125 sync speed, means to use 7 stop ND	f1.4	ISO100	1/125 sec	f16→f1.4, 7 stops
make ambient 1 stop darker than flash, means 7+1=8 stop ND	f1.4	ISO100	1/125 sec	f16→f1.4, 7 stops + 1 stop flash fill
	f2.8	ISO100	1/30 sec	f2.8 lens
if also with motion trail of background people, like 8 sec, then it need to turn 1/125 into 20“, means 8+10=18 stop ND	f1.4	ISO 100	8”	1/125→1/60→1/30→1/15 →1/8→1/4→1/2 →1“→2”→4“ →8”
if you able to stop down to f8, you just need 18-5=13 stops ND	f8	ISO 100	8“	f1.4-f8, 5 stops

Situation 2: Night time (Ambient Light: EV 3)
- answer: Night is like a built-in ND for the sky, means it is 15-3=12 stops cut from day light settings.

case	F	Iso	Shutter	note
normal correct setting	f1.4	ISO100	1/4 sec	f16→f1.4, 7 stops; 1/125→1/4, 5 stops
f8 landscape setting	f8	ISO100	8” sec	f16→f8, 2 stop, 1/125→8“, 10 stops
1/125 sync speed not affect slower shutter speed	f8	ISO100	8” sec	no change
flash has no impact on ambient, flash ⇒ portrait, shutter ⇒ ambient	f8	ISO100	8“ sec	1 stop flash fill
for 20” or 60“, 3 stops ND is enough or just blend 3 shots of 8”	f8	ISO 100	8“	8” → 15“ → 30” → 60“

conclusion

for a f2.8 lens, you need 3 stop of ND is good enough for day and night use
for a f2.8 lens with fill flash, you need 6 stop of ND to overpower the sun flash at wide open.
for a f1.4 lens, you need at least 6 stop of ND for day time use, and 10 stop ND for overpower sun flash at wide open.
3 stop of ND is good enough for any night shots

ND filter brands and naming

Haida Neutral Density Filters’ Factors:

Neutral Density	Exposure Adjustment	Light Transmission
ND0.3 (2x)	1 stop , reduces ISO by 1/2	50%
ND0.6 (4x)	2 stops, reduces ISO by 1/4	25%
ND0.9 (8x)	3 stops, reduces ISO by 1/8	12.5%
ND1.8 (64x)	6 stops, reduces ISO by 1/64	1.0%
ND2.7 (400x)	9 stops, reduces ISO by 1/500	0.25%
ND3.0 (1000x)	10 stops	0.1%

haida 6 stop and 10 stop ND
- review: by edutilos
- case: photo by nitewalk
note about Haida海大 price
- PROII级多层镀膜 vs normal (price increment factor)
- 超薄 vs normal (price increment factor)

link
- Haida海大超薄PROII级多层镀膜减光镜MC-ND1.8 (64x) 49mm (琪琪摄影俱乐部) 128 link
- Haida海大超薄型 ND1.8 (64x) 49mm 中灰密度镜减光镜 84 link