Put a filter behind the lens?

[jase]

So, as some of you guys might know, I am a big fan of the Tiffen Ultra Contrast Filter. I get awesome results (for my taste), yet I am about to drop it.

Why? Because Shooting with the sun pointing in whatever angle to my lens yields an image with so much flare, that i get one big misty mess. No sunhood helps, hell even when I use my whole palm of my hand as a sunhood, it only helps in some cases, yet not all of them.

However, since I like this filter so much I was thinking the following: cant i just put it behind the lens instead of in front of it to avoid this huge amount of flare? Of course, even if this would be possible, it is next to impossible getting the filter glas behind the lens. But how about using a speedbooster and put the thin filter glas on top of the filter and yet behind the lens? Is this a stupid idea because the flaring would still be the same regardless the position of the filter? Maybe @Brian Caldwell could chime in...

[Chris Oh]

This is from 2012, just from quick google search,

"Filters mounted between the lens and imager WILL change the focus characteristics of the system. Lenses designed to have a filter on the rear must always have a filter installed to focus correctly - if you don't need ND, then you must put a clear filter on the rear or you will lose infinity focus or at least throw off your marks significantly. Cameras with built-in ND have that glass factored into their design as well.

Not as simple as just slapping a filter in the cavity."

http://www.dvxuser.com/V6/archive/index.php/t-278342.html

[Geoff CB]

Stretch a stocking/pantyhose around the rear element and you will get a softening effect without the flares.

[jase]

9 hours ago, Chris Oh said:

This is from 2012, just from quick google search,

"Filters mounted between the lens and imager WILL change the focus characteristics of the system. Lenses designed to have a filter on the rear must always have a filter installed to focus correctly - if you don't need ND, then you must put a clear filter on the rear or you will lose infinity focus or at least throw off your marks significantly. Cameras with built-in ND have that glass factored into their design as well.

Not as simple as just slapping a filter in the cavity."

http://www.dvxuser.com/V6/archive/index.php/t-278342.html

Thanks for the thread, good read.

Yet, today we have adapters for mirrorless that allow the placement of the nd behind the lens - and no one complains about loosing infinity focus.

Some other quote from this thread:

Quote

A filter behind the lens will throw focus off by 1/3 the thickness of the filter used.

Well, knowing that my filter is a fraction of a millimeter and multiply that even by 0.3 - thats like nothing.

[Brian Caldwell]

11 hours ago, jase said:

........But how about using a speedbooster and put the thin filter glas on top of the filter and yet behind the lens? Is this a stupid idea because the flaring would still be the same regardless the position of the filter? Maybe @Brian Caldwell could chime in...

It depends a lot on the lens.  For some lenses, such as the 50/1.2 Nikkor, there is almost no space between the rear element of the lens and the front element of most  Speed Boosters.  I would hate for you to crush your filter between two lens elements!

[jase]

17 minutes ago, Brian Caldwell said:

It depends a lot on the lens.  For some lenses, such as the 50/1.2 Nikkor, there is almost no space between the rear element of the lens and the front element of most  Speed Boosters.  I would hate for you to crush your filter between two lens elements!

Thanks Brian! But other than the crushing aspect, what do you think? And do you know by chance, how much space we have between the Sigma 18-35 and the metabones xl ef?

[Justin Bacle]

On my anamorphic setup, I put the ultra contrast filter between the adapter and the lenses for best results  So i'm pretty sure you can do the same

[jase]

Just now, Justin Bacle said:

On my anamorphic setup, I put the ultra contrast filter between the adapter and the lenses for best results  So i'm pretty sure you can do the same

Ha, now it gets interesting! Can you confirm that there are less issues with flare with such a setup? 

[Justin Bacle]

Flaring is different :
- There is less flaring when a bright source is outside the frame -> less contrast loss and bloom
- You get internal reflections -> More optic flares

It really depends on the look you want. I can shoot tests this evening if you want with both configurations

[jase]

1 minute ago, Justin Bacle said:

Flaring is different :
- There is less flaring when a bright source is outside the frame -> less contrast loss and bloom
- You get internal reflections -> More optic flares

It really depends on the look you want. I can shoot tests this evening if you want with both configurations

That would be great! In general, I just want to be able to shoot in a bright source. I totally accept that the image changes (since this is lens dependent), but at least I want to be able to see something at all :D

[Brian Caldwell]

7 hours ago, jase said:

Thanks Brian! But other than the crushing aspect, what do you think? And do you know by chance, how much space we have between the Sigma 18-35 and the metabones xl ef?

Its a little complicated due to the fact that the outer surface of the Speed Booster is concave.  But you should have at least 1mm of clearance with this particular combination.  Note for anyone else reading this post that the Speed Booster XL for m43 has more clearance than a Speed Booster Ultra for APS-C.

[jase]

Thanks again, Brian! Do you think that i have to cut my filter glass in such a way that it fits the diameter of the speedbooster glass? Otherwise it would have to rest on the black surface and this will likely to break the filter when attaching a lens?

[bunk]

Apart from how you want to place the filter inside the speedbooster (sillyputty comes to mind) and keep it there, I think you will reduce the effectiveness of the filter significant.
The APS-C lens through a speedbooster will pass almost all light to the m4/3 sensor and thus in effect use the complete filter diameter of 72 mm. The effective diameter of the lens inside the speedbooster is only 32mm. That's trashing a lot of filter.
Just something to consider.

[Justin Bacle]

Very unscientific test (as I don't have step-up and step-down rings nor do I have a Tripod as I am in a Hotel for work right now)
Used a flashlight to create side lighting.

But here it is. I think I proved your point

No Ultra contrast filter :

Filter In Front of the anamorphic :

Filter between the adapter and lens (sorry for being a different shot, as I did have to put everything on a table) :

[jase]

Thanks! This seems to prove in turn @bunk's theory: i would say that placing the filter between adapter and lens yields an image that has much lens flare/haze, yet the filter effect is reduced. I think i could live with that, awesome @Justin Bacle

[noone]

What lenses are you using?       There are some that take rear filters or have a filter drawer.       Mostly it will be longer tele lenses that have a rear drawer slot but there are others it seems (mostly wide angles on FF).

 

 

[sanveer]

On 03/11/2016 at 10:43 PM, Justin Bacle said:

Very unscientific test (as I don't have step-up and step-down rings nor do I have a Tripod as I am in a Hotel for work right now)
Used a flashlight to create side lighting.

But here it is. I think I proved your point

No Ultra contrast filter :

Filter In Front of the anamorphic :

Filter between the adapter and lens (sorry for being a different shot, as I did have to put everything on a table) :

How about placing a Polariser or regular Multi-coating UV Filter in front of the lens? Does that help, without reducing the effect of the Ultra Contrast Filter by too much. 

[John Brawley]

You will definitely affect the collomation of your lens by putting a filter at the rear. No question. Behind the lens even a small amount counts for a lot. 

Some cameras (Panavision) allowed for rear filtering by having a filter slot near the gate but you always have to have a clear in to maintain lens collomation.

You also need to expect that the filter characteristics will change.  The filter will have a different effect, in my experience it's more heavy handed, which is why we don't tend to see it done much anymore.  

So you might like the 1/4 Low Con but you'd need a 1/8 behind the lens and it will still feel like it's doing more than the 1/4 in front.  

Consider that a low con is doing the same thing that's accidentally happening with your flare...milking the blacks.  If so, do you then just take then Lo con out for that shot ?

There are also some great filter tray tilting options  as well. Bright Tangerine have a tiltable filter tray, and even a bracket that can tilt the whole mattebox.  I think that might be the easier more practical solution.

 

JB