Team-BHP - The DSLR Thread

Quote:

Originally Posted by it_inspector (Post 1588353)

There are different kinds of Photographic Filters.

Polariser filters are used to reduce reflections and darken the images to give some contrast. Pretty much any shot where there is water or cars need a polariser.

Now polariser filter is pretty simple to use. Its split into 2 rings, rear ring mount it to the lens while front ring houses the polariser and it can be rotated.

Since polariser affect focusing and metering in DSLR`s, you need to follow following path for using a polariser.

1. Compose
2. Adjust polariser
3. AF + AE
4. Shoot.

If your lens rotates front element while focusing, you will need to re-adjust polariser. So in order to use a polariser following will need to happen.

1. Compose
2. Adjust polariser
3. AF + AE
4. Adjust Polariser
5. Follow steps 2-4, till you get right AF & AE
6. Shoot

This can get annoying and tedious very quickly.

Now ND filters are quite a different breed and i love mine more than the DSLR itself. ND filters let you achieve that sometimes cannot even be done in Post Processing.

ND filters basically stop incoming light. Now what`s the point stopping all the light into the lens? Specially considering we sell an arm and a leg to afford primes with f0.95/f1.0/f1.2/f1.4

Well here`s the wrong thinking and unless we get our head around it, use of ND filter is not possible. We do not pay for f0.95/f1.0/f1.2/f1.4 lenses for huge amount of light coming in. Infact after f2.8 it really doesn`t matter that much. We pay for crazy slim DOF we get with such huge apertures.

But shooting in bright sunlight, well anything above f2.8 can blow highlights pretty quickly, even at shutter speeds of 1/8000. Now move the same day to a snowy mountain and issue becomes apparent, too much light everywhere. Well at f5.6 shutter speed if 1/8000. Shooting is almost impossible, here comes an ND filter to rescue. An ND8 filter will only allow 12% (actually a tiny bit over 12%) light, So shutter speed goes slower and we can use large apertures for crazy slim DOF.

Also ND filters are used to create a natural blur or longer shutter times during day for that amazing moving clouds effect.

Now there is another territory, HALF ND filters and HALF filters, mostly available with the likes of Cokin and Lee. Now AFAIK Cokin does have a P series adapter set which rotates opposite to lens`s front barrel on focusing, basically correcting the affect front barrel has while focusing.

I hope what i typed made sense, i am half sleep and in a hurry. If i am wrong anywhere please correct me. I will post some examples of ND8/ND10 filters use during day time.

Cheers

I have used the 18-55 DX the non VR lens with a polariser and have never found it too cumbersome. Usually one is focussing at infinity stopped down for landscapes and I see absolutely no problem in the front element moving as one can still rotate the filter after AF has been achieved so there is no question of the filter having moved after I have achieved focus lock. Maybe my technique is wrong and I was not aware of people rotating the polariser first before achieving AF.

I have often wondered whats the need to use f0.95/f1.0/f1.2/f1.4 lenses in bright sunlight when these were not really designed to be used in such scenarios. These are specialist low light lenses and using such wide apertures for bright sunlight is plain :Frustrati. Shallow DOF might be a reason but, gurus kindly correct me here, will it not be better to really shoot with a long telephoto to get the required DOF instead of using these noct lenses for bright sunlight and blowing out the entire frame? I have seen pros shoot with a 300 2.8 for glamour shots which would separate the subject from the back ground really well without blowing any highlights.

Quote:

Originally Posted by SPARKled (Post 1588737)

I have used the 18-55 DX ...snip...

Thing is addition of any filter of any thickness affects AF, how much, it depends on the combination of the lens and DSLR body. Similar to IR CUT filters, it varies with each DSLR design. Linear Polarisers affect AF more than Circular polarisers though.

First of all, using 300mm f2.8 ir not easy to use or ideal for glamour shots, since its focusing distance is not very close. Also the size and weight doesn`t permit much flexibility.

Are you sure, you are not confusing DOF with blur ???

Sure you can use 300mm f2.8 to seperate the person from background, but what background are we talking about?? In the middle of a party or on a terrace with few mountains as background?? In the middle of a party, seperating the subject from persons standin 20cms away requires shallow DOF.

Basically large aperture lenses can be used with a ND filter to achieve slow shutter speeds.

Also ND filters help produce natural effects that are otherwiser either very hard or impossible to do in post processing. Specially with clouds.

Cheers

Quote:

Originally Posted by it_inspector (Post 1588958)

I am not questioning the usefulness of ND filters or what are they used for, my point is whether it makes sense to use the noct lenses to take photographs in bright sunny conditions at F1.4 or larger. These lenses were not designed to do this. The 300 2.8 was an extreme case I told you and no doubt there are other better lenses to do this but surely no one uses a noct to shoot anything in the scenario that you have described. The 70-200 2.8 is a pretty good lens to do this and the 200 2.0 is even better at 200. And even if he/she used one of the super nocts, they would be stopping it down and still get appreciably decent thin DOF. Also I am not sure why any one would shoot clouds using an ND filter on a lens faster than 1.8 and that too wide open. What thin DOF advantage are we getting here?

Quote:

Originally Posted by SPARKled (Post 1589147)

These lenses were not designed to do this. The 300 2.8 was an extreme case I told you and no doubt there are other better lenses to do this but surely no one uses a noct to shoot anything in the scenario that you have described. The 70-200 2.8 is a pretty good lens to do this and the 200 2.0 is even better at 200. And even if he/she used one of the super nocts, they would be stopping it down and still get appreciably decent thin DOF. Also I am not sure why any one would shoot clouds using an ND filter on a lens faster than 1.8 and that too wide open. What thin DOF advantage are we getting here?

Those were just examples from google to show effects achieved via Nd filters. Nothing more.

About the thin DOF. I am just going to give a simple example with different lenses and different apertures or what dof you get. This is the only way i can make it clear why you can use noct lenses (btw canon used to make 50mm f0.95, so its not only leica) wide open during the day to get crazy yet CONTROLLABLE dof. And the lenses don`t need to be stopped down.

What DOF you get with different lenses at the same subject distance, shot wide open.

-Nikon 300mm f2.8G + d3 with a subject at 2.5m* (exactly minimum focusing distance) at f2.8 will give dof of 10.3mm or 1.03cm
-Nikon 200mm f2G + d3 with a subject at 2m away (just over minimum focusing distance) at f2 will give dof of 10.8mm or 1.08cm
-Nikon 70-200mm f2.8 + d3 with a subject at 2m away (around 1.3 times the minimum focusing distance) at 200mm f2.8 will give dof of 15.2mm or 1.52cm
-Nikon 135mm f2 DC + d3 with a subject at 2m away (just over double the minimum focusing distance) at f2.0 will give dof of 24.6mm or 2.46cm
-Nikon 105mm f2.8 + d3 with a subject at 2m away (nearly 7 times the minimum focusing distance) at f2.8 will give dof of 57.9mm or 5.79cm
-Nikon 85mm f1.8 + d3 with a subject at 2m away (over double the minimum focusing distance) at f1.8 will give dof of 57.4mm or 5.74cm
-Nikon 85mm f1.4 + d3 with a subject at 2m away (over double the minimum focusing distance) at f1.4 will give dof of 44.7mm or 4.47cm
-Nikon 50mm f1.8 + d3 with a subject at 2m away (over 4 times the minimum focusing distance) at f1.8 will give dof of 169mm or 16.9cm
-Nikon 50mm f1.4 + d3 with a subject at 2m away (over 4 times the minimum focusing distance) at f1.4 will give dof of 132mm or 13.2cm
-Nikon 50mm f1.2 + d3 with a subject at 2m away (exactly 4 times the minimum focusing distance) at f1.2 will give dof of 113mm or 11.3cm
-Noctilux 50mm f0.95 + d3 with a subject at 2m away (exactly double the minimum focusing distance) at f0.95 will give dof of 84.5mm or 8.45cm
-Nikon 28mm f2.8 + d3 with a subject at 2m away (exactly 8 times the minimum focusing distance) at f2.8 will give dof of 887mm or 88.7cm
-Nikon 28mm f1.4 + d3 with a subject at 2m away (exactly double the minimum focusing distance) at f1.4 will give dof of 428mm or 42.8cm
-Nikon 14-24mm f2.8 + d3 with a subject at 2m away (around 7 times the minimum focusing distance) at 24mm f2.8 will give dof of 1261mm or 126.1cm
-Nikon 14-24mm f2.8 + d3 with a subject at 2m away (around 7 times the minimum focusing distance) at 14mm f2.8 will give dof of 12600mm or 1260cm or 12.6m

Now can someone please choose a lens that can be shot wide open for portraits during bright sunlight.

I can give scenarios but the fact is, 50mm and 85mm lenses are best for shooting wide open. You get the sweet spot for dof, even at f0.95 you get enough dof to get almost complete face in focus. When you go between f1.2 to f1.4 its almost perfect dof for isolating everyone from the subject.

**Unfair treatment with inclusion of 135mm f2 DC since it lets you focus-defocus out-of-focus background. If you think 85mm is the ultimate boken machine, then you need to shoot with 135mm f2 DC, since this is the ultimate boken machine and no 85mm stands ground in front of it.

I Hope doing all these calculations was worth it and i was able to put my point forward without sounding rude.

Cheers

Quote:

Originally Posted by it_inspector (Post 1589363)

Yes I agree that 85 on full frame and 50 on crop sensor is the best focal length for portraiture especially indoors where space is a problem. Outdoors I would like to go longer if possible for better isolation. I just wanted to put forth no one will ever shoot landscapes or clouds or snow even with ND filters mounted on these lenses wide open for the sake of DOF as I infered from your post.