If this question has been asked and answered many a times, please link me to the thread. If not, I like to know why we tend to lose nice looking bokeh when using the 35mm adapter? Is it the lens or the adapter that we use? If I use the stock lens that came with my EX1, the bokeh are much better looking than when using it with my Nikon lenses and Letus EX 35mm adatper. Any explanation why?
Why do we loose bokeh when using 35mm adapter?
- Thread starter Lor
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Chris Santucci
Veteran
I think you are experiencing "different" bokeh, not a loss of bokeh.
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The DOF adapter bokeh is pretty much a compromise between low light loss (not so nice bokeh) and mainstream aesthetics (common bokeh circles). With an adaptor that doesn't lose so much light as "the others" you got mushy, undefined circles of confusion and when the adaptor loses as much as the discontinued SGpro it will produce the classic, common bokeh.
Compromise between light loss and aesthetics, that's about it.
Do you care about what you've been accustomed to and bring in double the lightning power or you will get accustomed to that "different" bokeh?
Photographers see the difference right away but most video guys enjoy the subject to backround sepatation without seeing the aesthetical differences at first.
I've always imagined a hysterical videographer who's just got a DOF adaptor screaming: "Holly mother of fu(k I can tell my story like in the cinema, you know, I can separate my subjects from the background, you know, when ther's a whispering woman on the foreground and not the trees on the back that whisper... ohsh... oush... ohshi*"
Me being a bit too cynical.
Close your 35mm lens to f4 and that magic common bokeh forms again even with the Letus Extreme I assume, you'll lose the light anyway and f4 is much easier to work with at the end of the day.
T
Compromise between light loss and aesthetics, that's about it.
Do you care about what you've been accustomed to and bring in double the lightning power or you will get accustomed to that "different" bokeh?
Photographers see the difference right away but most video guys enjoy the subject to backround sepatation without seeing the aesthetical differences at first.
I've always imagined a hysterical videographer who's just got a DOF adaptor screaming: "Holly mother of fu(k I can tell my story like in the cinema, you know, I can separate my subjects from the background, you know, when ther's a whispering woman on the foreground and not the trees on the back that whisper... ohsh... oush... ohshi*"
Me being a bit too cynical.
Close your 35mm lens to f4 and that magic common bokeh forms again even with the Letus Extreme I assume, you'll lose the light anyway and f4 is much easier to work with at the end of the day.
T
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This will probably be an unpopular view, but TBH I find the 35mm adapters totally unrealistic looking. Does that make them look bad or just different? Well, thats a preference thing. But please dont beat me up for having an opinion. The 35mm adapter makers though are to be commended on what they have created and sell at reasonable prices. Personally Im not a fan and would rather shoot through a standard HVX, EX, DVX etc etc lens and use what I know to create the look I want, then again Id prefer to shoot on a larger sensor / ccd like 2/3" that give me even greater control. Glass in front of glass in front of glass in front of glass isnt my first choice.
But Lor, I agree I think the boke (correct Japanese spelling), is not the same and isnt as nice, no matter how you set up.
For the record though, I have seen a couple of pieces where I thought the unusual look (again thats my opinion) of a 35mm adapter was used very well and helped the piece. One of these was a TV commercial.
Noel (Former Letus and M2 owner)
But Lor, I agree I think the boke (correct Japanese spelling), is not the same and isnt as nice, no matter how you set up.
For the record though, I have seen a couple of pieces where I thought the unusual look (again thats my opinion) of a 35mm adapter was used very well and helped the piece. One of these was a TV commercial.
Noel (Former Letus and M2 owner)
JohnLeeFilms
Active member
Hey guys. I have done some comparisons with the G35 and the native Bokeh of my camera. It's an exact match. The material used for the focusing screen for the G35 produces a bokeh that is a match to the actual bokeh seen in film and photographs. I can post grabs later.
ecking
Veteran
I do agree that adapters do give off a different bokeh and different adapters and ground glasses can given off vary degrees of a close match to film bokeh. But I gotta say if an audience is watching your product(commercial, movie, music vid, etc.) and they're actually looking at your bokeh the product must not be very good. Unless you're only interested in showing it to people like us. It seems like at this point all adapters have some ability to offer bokeh that most people would consider good enough.
Popsiclestand
Well-known member
I think people misunderstand the purpose of bokeh (or, yes, the correct Japanese phonetic Romaji spelling Boke) in 35mm adapters. It's not to get a "realistic" look, it's to mimic the depth of field present in film which it does to a great degree.
If you look at a movie shot on actual film using film lenses, you will see that it is not very "realistic" (defined as mimicking what the human eye sees). The camera is a device to tell the story in a certain way, to draw the eye to a certain spot. The use of bokeh is just one of the tools to do this. Most people are used to film and equate the use of bokeh to a certain quality and a certain feel. Which is why the 35mm adapter business is flourishing in a age of video -- despite the light loss problems inherent to them..
There are certain applications where a 35mm adapter is a hindrance. Some people want to see everything in focus. I, personally, don't like having my eye distracted from the key action, thus I salivate over good bokeh. But then again, my primary format is dramatic narrative where I think the creative use of bokeh works best. I hate the sharpness of standard video lenses personally (even though they are some amazing bits of glass). Makes my eyes bleed, lol.
I've also seen some pieces hammered to death with over-used DOF -- forgetting the primary purpose of using it. But those people would have made the same mistakes on film when choosing their lenses anyway...so...
Now whether you want the "swirly circle" bokeh or the "finger smudge" bokeh is all up to the adapter you choose when shooting on video. I can tell you that it's the same with film. Shooting 16mm with some zoom lenses on some cameras produces an annoying leaf-pattern bokeh that I can't stand.
If you look at a movie shot on actual film using film lenses, you will see that it is not very "realistic" (defined as mimicking what the human eye sees). The camera is a device to tell the story in a certain way, to draw the eye to a certain spot. The use of bokeh is just one of the tools to do this. Most people are used to film and equate the use of bokeh to a certain quality and a certain feel. Which is why the 35mm adapter business is flourishing in a age of video -- despite the light loss problems inherent to them..
There are certain applications where a 35mm adapter is a hindrance. Some people want to see everything in focus. I, personally, don't like having my eye distracted from the key action, thus I salivate over good bokeh. But then again, my primary format is dramatic narrative where I think the creative use of bokeh works best. I hate the sharpness of standard video lenses personally (even though they are some amazing bits of glass). Makes my eyes bleed, lol.
I've also seen some pieces hammered to death with over-used DOF -- forgetting the primary purpose of using it. But those people would have made the same mistakes on film when choosing their lenses anyway...so...
Now whether you want the "swirly circle" bokeh or the "finger smudge" bokeh is all up to the adapter you choose when shooting on video. I can tell you that it's the same with film. Shooting 16mm with some zoom lenses on some cameras produces an annoying leaf-pattern bokeh that I can't stand.
Many thanks for those who responded. Basically I just like to know why the nice circle or hexagon shapped bokeh got changed to mushy confusion or blurieness look when using 35mm adapter. Someone suggest that it has to do with light lost, so if increase to f4 I can get it back, correct? Some say it has to do with the type of glass the 35mm adapter is made off, if so, there must be some 35mm adapter that uses good glass so that this bokeh does not get changed drastically, correct?
JohnLeeFilms
Active member
Anyone correct me if I am wrong, but I think it has to do with the amount of diffusion the 35mm adapter is giving. Most adapters use a ground glass (glass that is actually ground) and that is where you get the ability to have shallow DOF. Now depending on how it is ground will dictate how much diffusion you have. If you don;t have enough diffusion, then you will get a glow or a guassian blur. The SGPro comes pretty close to a good doffision for bokeh, but still not an exact match. If you look at footage from the G35, I beleive you will see the bokeh that you are after. They use a different focusing screen altogether which allows for proper diffiusion. I have tested the G35 bokeh against my actual camcorder bokeh and the bokeh in photographs and actual film, and it is an exact match.
jls4
Veteran
Lor, if you get a SGpro/SG Blade you'll get nicer bokeh. I use a Letus right now, but I'm seriously looking at the SGBlade because of the bokeh. There is a point where you want your shots to be beautiful, not just with small Depth of Field. And if a "true indie filmmaker" really wants to make a movie, they'll be ready for lots of light. 1Ks, 2Ks, 5Ks, etc. They will not shy away from more light to get the "look" they want. Also it is to be noted that 35mm lenses from movie cameras (from what I've seen in tests) have a larger Depth of Field than 35mm adapters. So even a 35mm adapter set at f5.6 with camera at f5.6 will be shallower than a 35mm camera at f5.6.
That's the biggest issue I personally have with DOF Adapters. However there are ways to increase the DOF by closing the iris even more f/8 over f8 (adding 4x the light), I hope to be able to go f5.6 over f8.0 (on camera) on my next movie. Last movie we had very little light and a light sucking HDV camera, so I was at f1.8 over f2.0 for most of the movie with about 3 inches of Depth and lack of full sharpness on the sensor. My goal right now is to try to get to 10 inches of Depth.
That's the biggest issue I personally have with DOF Adapters. However there are ways to increase the DOF by closing the iris even more f/8 over f8 (adding 4x the light), I hope to be able to go f5.6 over f8.0 (on camera) on my next movie. Last movie we had very little light and a light sucking HDV camera, so I was at f1.8 over f2.0 for most of the movie with about 3 inches of Depth and lack of full sharpness on the sensor. My goal right now is to try to get to 10 inches of Depth.
mentatDUKE
Veteran
How much light will be required to get f5.6 over f8.0 though? Huge HMIs?
I have a similar goal except I feel f4 over f4/f5.6 is more feasible.
I have a similar goal except I feel f4 over f4/f5.6 is more feasible.
Deuceofspades
Veteran
If you are working with LetuxExtreme (vibrating ground glass) you will not be able to close your iris and lense down too much. Doing so will produce noticeable artifacts, especially on plain backgrounds such as sky, walls etc...
Plus speed must be no faster than 120, so all in all it will be hard to cut down a significant amount of light without having artifacts.
Plus speed must be no faster than 120, so all in all it will be hard to cut down a significant amount of light without having artifacts.
jls4
Veteran
You have 2 things you must think about. First the camera. The camera settings need to be f4.0 or higher for good sharp results.
Then your lens on the adapter needs to be f4.0 - f8.0.
The above has to do with Depth of Field not Bokeh. I have no idea if the bokeh will be better with the above scenario or not. I'm such a fan of the SGBlade/Pro that I've focused more on their versions of bokeh than what can be achieved from a Letus (somthing maybe I need to research). The above should give you an estimated 6-8 inches of sharpness in floating space - meaning whatever is in focus - 4 inches in front and 4 inches behind it will have perfect focus. Now this 6to8 inches is a guess - not actual number. That varies from lens to lens and distance to subject.
You have to close both irises for best results.
Yeah having lots of light is important. But once you're shooting 1/2 chip, it shouldn't be so bad - based again on my estimates, not any actual data.
But stops work like this. If when the camera is wide open (we're not talking adapters here, just basic f-stop) you can see your subject in perfect exposure with a tungsten 75watt lamp, then to recreate the same thing at f5.6 it'd take a 2400w tungten lamp.
75w - Open
150w - f1.4
300w - f1.8
600w - f2.0
1200w - f4.0
2400w - f5.6
Basically you have to Double your lumens/foot candels for every stop you go up. But as you go up, things get sharper and the depth of field gets greater.
To put in perspective of what happened to me on my last movie.
F-stop... TunstenWatts.... Relative Line Sharpness.... Depth fo Field
Open........... 75w......................... 680 lines.................. 2 inches
f1.4............ 150w........................ 700 lines.................. 3 inches
f1.8............. 300w....................... 730 lines................... 4 inches
f2.0............. 600w...................... 750 lines ...................6 inches
f4.0............ 1200w...................... 800 lines................... 8 inches
f5.6.............. 2400w.................... 900 lines.................. 10 inches
f8.0............ 4800w..................... 1080 lines................. 12 inches
These numbers ARE NOT ACCURATE. They are just for illustrative purposes, but you can see how the more you close the iris the sharper the images become and the more depth of field you will see. But you have to double the light each time. This is also importaint when using a 1080p camera because just because the camera CAN capture 1080 lines of resolution, doesn't mean it is capturing it. Cinevate has some videos on it and I think SGpro does as well. They show the difference in the camera set at f5.6 vs f8.0. They also show a few videos on DOF.
This is really important info if you want to work with Depth of Field. 2 inches of DOF is hard to work with. If the actor breathes you'll loose him/her into bluriness. 6 to 8 of DOF is more workable and 12-18 inches of DOF is close to perfect (at least for me).
Okay, so in my simplicity thinking, if the lost of nice bokeh is mainly due to light, instead of fooling around with f-stop on both the camera lens and the Nikon lens, isn't it easier to make 35mm adapter that the user can adjust the light similar to built-in camera ND filters? Or is this a nonsense idea?
Will Clegg
Veteran
You can only adjust the light transmission by changing out the ground glass or imaging screen. So far, only Brevis and M2 offer interchangeable screens that allow this.
I have not used the Brevis, but with the M2 it's not exactly a simple process - you have to take the adapter off of the rails, open it, remove a bolt, swap out the screen, replace the bolt, test to make sure the alignment is right, ensure everything is dust free, close the adapter, and mount it on the camera and rails again. This takes a minimum of five minutes and needs to be performed in a dust-free envirnoment. And the results are slightly different, so you can't really do it in the middle of a scene.
I have not used the Brevis, but with the M2 it's not exactly a simple process - you have to take the adapter off of the rails, open it, remove a bolt, swap out the screen, replace the bolt, test to make sure the alignment is right, ensure everything is dust free, close the adapter, and mount it on the camera and rails again. This takes a minimum of five minutes and needs to be performed in a dust-free envirnoment. And the results are slightly different, so you can't really do it in the middle of a scene.
Douglas Villalba
Well-known member
That doesn't make any sense to me.
Except for the Letus Ultimate and the G35 you can't go higher than f5,6 on the adapter lens.
On the other hand a camera fully open is between f1.6 and f1.7 depending on the camera. You add the adapter and when you zoom in it closes to around f2.4. Your starting point should be f2.4
Were do you come up with the resolution chart? Most lenses are at their prime 2-3 f stops from fully open and from fully close. One thing is for sure, none of the cameras that we use an adapter on gets 1080 resolution independent at what f stop you are set.
So, what happen to f2.8 on you W/f stop calculation?
jls4
Veteran
Hey Douglas, I did that chart quickly. That's why I said it wasn't accuate. I was just trying to illustrate a point. You're right in that it should've been 1.4, 2.0, 2.8. anyway the point I was trying to illustrate is that the Camera does effect the line amount. I think it was the SGPro folks that figured it out when they were doing acromat testing for the EX1. They showed two pictures from a resolution chart. One image the camera was at f5.6 the other f8.0 and you could easily see a huge difference in the amount of lines captured by the camera. They advised that people stop down on both the camera AND the 35mm lens in order to get images as sharp as possible. I tried to find the thread, but I don't remember where it is. but I'm sure if you spend some time searching you'll find it.
As for the ability to stop down below f5.6 that wasn't part of my main point. Right now I'm looking towards the SGBlade which can do anything, so can the new Letus. My point was about sharpness and clarity, not the limitations of an adapter. But this would be importaint in choosing which adapter to buy - so I guess it's something to think about.
The main point I'm making is that light effects your image and sharpness. The reason why I brought this up in regards to the bokeh discussion because there are lots of things to consider. True Depth of Field, Sharpness of the Image being captured, Bokeh, Color, etc. You don't want to focus so much on one item and loose another. The best way to get around it, is to spend some money on some lights. Movie Sets are lit up for a reason. :beer:
On my last movie we were at Camera(f1.7-2.0), Lens(1.4-1.8) and boy did we have like 1 to 3 inches of depth the whole movie. Shots were constantly going blurry as Actors moves around. We tried to edit around the problem, but still ended up with it about 7 to 10% of the time.
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