Ground Glass - Large Format Friday
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- เผยแพร่เมื่อ 29 มิ.ย. 2024
- A simple but necessary component to many large format cameras, the ground glass plays a critical role in the LF experience. Today, I'm going to shed some light on the translucent surface we use to compose and find focus.
00:00 Intro
00:29 Ground Glass
01:42 Shading Ground Glass
03:30 Viewfinders
04:11 180 Degrees Flipped
05:41 Fresnels
09:23 Broken Ground Glass?
11:33 Cleaning Ground Glass
How to Make a Ground Glass: • Making a Ground Glass ...
Questions? Send me an email: largeformatquestions@gmail.com
Content by Mat Marrash: www.matmarrash.com
Support the Channel here: paypal.me/matm
#largeformat #filmphotography - แนวปฏิบัติและการใช้ชีวิต
Pick up a broken flat screen tv from a dumpster - disassemble the screen - great plastic " ground glass" between the layers .
Fresnel + protector = overhead projector screen. ( from the junk store, I paid $ 3 for a perfectly good projector with bad bulb ) Easy to cut .
But the best - ground your glass ! It's easy . ( cut the glasses from a junk scanner - better, thicker than window . )
Now that's a super resourceful DIY tip, thanks Peter!
The way you pointed correctly to where the playlist link comes just shows the production value of this channel, excellent!!
Mat, I always look forward to your new video each week. It completely caught me by surprise when you mentioned my video! I appreciate you mentioning that video and I am grateful for your channel! Looking forward to more LFF! Sincerely, Tony
Thanks Tony! Your video has saved me hundreds of dollars over the years and I wanted to make sure folks know about it. :)
Me and my brother-in-law used your method to make our ground glass for our box camera! Funny seeing you here!
@@dctimagery I appreciate you Connor! The LF community is small enough that you do get to know each other. Happy shooting! Tony
There’s just something magical about seeing an image focused onto ground glass. Great informative video, Mat!
Thanks Eric, the ground glass really adds to the LF experience!
As a tecnicean I like to make and modify my own stuff. I replaced my two original intrepid ground glass, because they had too many lines on them for my liking, with two new picture frame glass that is 2mm thick, and ground slightly brighter glass with 800grit silicon carbide. Afterwards I market the ground side with thin pencil lines in 1/3 horizontal and vertical lines plus a small center cross. It is a simple job to do and you can always have a spare handy for the day you break one.
Keep those videos comming. 👍
Hi Philip, I’m struggling to find focus with the intrepid ground glass I do find it quite dark and I’m struggling to see tack sharp. As it’s my first 4x5 I’ve nothing to compare it to. Just wondered if you had a similar experience before you changed. Have to say on this video the ground glass looks so much clearer than my intrepid.
@@altully7006 Thanks for the question. I do not know what lens you are using but always focus at maximum aperture, fully open. Yes a dark cloth, black on the inside to help if it is bright outside, and use a loop, I use a X6 or X8. Find a small sharp edged item or good contrast item in your seen, and use that to focus. once you have a basic focus, find a near item and a farther item to fine tune your focusing with any movement you make, but after each movement continue to focus each time fine tuning closer to the perfect. Use the loop, I do. And do not forget to lock everything down once you have made movements, tripod, camera, front standard and focus lastly.
As Mat previously said learn the dance, and what I mean by that is go out with your camera set it up and focus. No film needed. Then find another seen, and Focus. then find another seen. It is all just practice, and after you have done this 8 or 10 times, you should start to get a feel for focusing.. Start with simple subjects, a blank surface with just one object to focus on. then progress to foreground and background focusing, again simple seen two objects.
I hope that helps. Good luck.
@@phillipmurray8848 thanks Philip, appreciate you taking the time. I am mainly using a 135 f5.6 which is quite bright, having added a fresnel and a dark cloth I think the answer could be in buying a better quality loupe than what I use at the moment.
LFF!! NEW HAIRCUT! LIFE’S GOOD!!
Thanks! When the hair changes I always forget it's more of a shock to everyone else because they have to see it more than I do. ;)
They also used to scribe lines into groundglass with a glass etching tool. You’ll see it occasionally with reflect type cameras, and with cameras with revolving backs so you knew which way your composition was. Sometimes you’ll see scribed/etched grins too, but those are less common.
That's pretty cool and makes a lot of sense to try and combine the two onto one piece hitting the film plane.
I am so glad i watches this video!!! I am new to large format and recently got a vintage crown graphic but, couldn't find out why my negatives where out of focus. After seeing this I found out my camera had a Fresnel with the ground glass. The Fresnel lens was in front of the ground glass (toward the lens) and the ground glass was backwards!!! I'm hopping this solves my issues!!
Thanks doing this video! Very timely for me. The night before you posted this my ground glass broke. You provided some great solutions.
Glad this video could help, Jeff!
@@MatMarrash It sure did, I made a new ground glass yesterday and a plexiglass cover today for my Bender 4x5 that I built in 1994. Very encouraged to be shooting with it again. :)
@@jeffdevries5044 Wow that's great news! Been a while since I've heard mention of a Bender camera kit. Have fun getting back to LF.
Another substitute if you happen to break your ground glass is spray frost. If there is a glass shop near by have them cut a piece of glass to fit your camera, and spray a coat or two on the back side with the spray frost. When I got my 8x10, the ground glass was broken in shipping, I used this option or about a year. Then I went to a custom glass shop and got a piece of etched glass to fit my camera. Since have replaced my ground glass with one from Young Camera in Washington, I keep the etched glass as a spare, and bring a can of spray frost.
Good tip, thanks for sharing!
Another stellar vid but I hope you're planning on growing out that pomp out again! It was legendary.
It may take some time, but it will return!
Another great video, Mat!
The hack with the tape blew my freakin' mind!
Hi Matt, excellent as always.
Just one word of advice about breaking the Ground Glass when on your camera. Always check to see that all the glass has been removed. Extend the bellows fully and check in the folds in case shards of glass are trapped which can pierce the bellows leading to more problems.
Hey William that's a great tip!
Great video and informations ,incomparable Large Format!!!!
Thanks so much!
Thanks for the acrylic gg tip! Gonna make one this weekend as I wait for my replacement Toyo 810M is mid Pacific from Japan
Glad I could help Ron! Fun fact: they guy that made me my acrylic ground glass is also a Toyo 810M user!
@@MatMarrash I literally got the gg in the mail from japan, removed my homemade acrylic gg, install the NOS Toyo gg, and in the excitement, forgot to clip the back retainers and it fell off and broke. time for a drink and reinstall the acrylic gg.
An especially good and helpful episode. Loved it.
Glad it was helpful!
Another great episode! I just recently had to learn how to make my own for a DIY 13x18 back, and Tony's video were also very helpful.
Thanks Rodrigo, DIY is a great option for sizes larger than 4x5!
I found that Fresnel lenses are tuned to a specific focal length lens. I have one that works great for a 150mm lens. It's so bright, I don't have to use the focusing cloth. But with a 90mm or 210mm, I'm chasing a bright round hole across the frame. I'm going back to straight ground glass.
great video, one hint, if you have a broken Ground Glass, use a viewer for 6x12 or 6x17 ( the ones to frame-up the shot with a panoramic roll film back), they use the grafflock fittings on the international back, just remove the frame part ( the one which holds the Glass, and has the spring levers pivot on), have to switch out for film and are limited to 6x6, etc roll film backs, as the spring frame IS essential to fitting a double_darkslide into the camera, as this is the movable vice jaw which holds the holder to the focus plane of the camera; but at least you can still shoot :-).
Missed critical focus 4 times yesterday on my ground glass! Just a hair off in low light but my loupeless behavior caught up with me and affected otherwise really good shots. Buying a loupe ASAP.
I have a Sinar P2 with the original ground glass and with that I want to send out a smal warning about cleaning its ground glass. It was quite dusty when I got it and decided to give it a gentle rinse under luke warm water. As I did that the composition lines just melted off the glass surface and down the drain. I guess with age, these glued on stripes loose its stickyness and in my case a little bit of water was all that was needed for them to be removed. Be careful.
Thanks for the cautionary tale, Johan! I'll be sure to keep my Sinar P2 glass away from warm water when cleaning.
great idea that Scotch magic tape for ground glass hack. at 9:41 convincing demo. 👌🏻
Desperate times call for desperate measures!
Yay!!! It’s friday!! Always look forward to the LFF series.
Never thought of using tape for a ground glass! I’ve used wax paper flattened on some clear acrylic and that worked pretty well. LF shooters are a resourceful bunch 😃
It's another one of the great parts of working in large format! :)
Hi Mat, what amazed me when beginning with LF was that after some initial dizzyness when looking at a groundglass, I tend to completely forget about a groundglass image being upside-down and reverse. One reason for this could be that for our brains inverting an image is a familiar routine as they're busy rearranging our retinal upside-down, reverse imagery all the time. To make things more complicated, a retina is curved, there's two of them and a suggestion needs to be created that we're standing upright in space instead of floating around disoriented. What an admirable thing our brains are ... Anyway ... thank you very much for another inspiring sequel of LFF!
How did you like the Alan Ross workshop btw? I had registered for a workshop with him at the JOBO plant in Germany last August. Due to pandemia it got postponed to next year; my plan is to maintain my registration (hoping there'll be a vaccine a year from now).
Have a good weekend :-)
Hey Norbert, that's a really great point about our vision. It really does feel natural after a while! If you have the chance to work with Alan, I strongly recommend it. He's a wealth of knowledge and an awesome human being.
Oh no, the surf wave quiff has gone!
Hi Mat.... thanks for the great video. I am building a 8x10 video camera and rather than the obscura variant, I would like to film the ground glass. I wonder why your intro has that strong brightness fall off and "lady with dog" at 2:27 has not? Maybe you can "enlighten" me??
Whoa, Media Division has watched one of my videos?!! I love your channel! The biggest difference between the intro and the later shots is the presence of a fresnel lens. A fresnel will brighten the center while falling off drastically at the corners; in your case of filming the ground glass, it will also show lots of little concentric circles in the shot. For the 8x10 video camera, I'd recommend a very, very fine ground glass without a fresnel.
Back at Uni 12 years ago I broke a GG & replaced it temporarily with an acrylic one I made at home...it was effective, lighter and I felt far less nervous about quickly setting up a shot if I needed to. I'm surprised there are no commercial ones available...glass is more rigid but I'd absolutely buy a professionally made acrylic one for when I'm traveling overseas etc.
Agreed on traveling with an acrylic GG! Fresnels and ultra-bright screens get a lot of hype, but they don't handle airport security the same.
Fresnel position is camera dependant. On a linhof master its on the backside not the lens side.
Mat, I ordered a fresnel/ground glass combo for my Crown Graphic. I was surprised to find that the ground glass was 100% transparent. No grind or etching of any kind. I thought they made a mistake. When i mounted them in my camera, i could not believe that i actually saw an image. I am guessing that the image is actually being displayed on the inside of the fresnel lens. The order is lens-> fresnel smooth side -> fresnel ribbed side-> clear glass-> my eyes. I have not heard of this in any of my readings. It seems to work though. I can’t imagine there would be any measurable difference between the fresnel and what would be the frosted side of the ground glass as they are touching. I will see on my next shots. Thanks for the video!
Thanks for the comment Ron! Many fresnel lenses are so easy to scratch that the clear glass serves as a protective overlay, sometimes with grid lines.
Dollar Tree carries these thin cutting board sheets made out of plastic. They come in two packs and are large enough to be cut to fit a large format camera. I've used them in the past to make light diffusers by sanding them, albeit with a very rough finish because I wasn't trying to get a super precise ground glass level surface, but with a much finer grit of sand paper I'm sure you could make something on par with the scotch tape option.
Certainly this isn't the ideal option, and actual ground glass would be better, but in terms of having something to keep in your kit for emergencies, they're plastic. They're flexible, they won't break, and they're 50 cents.
Just if you're going to do this, try to avoid washing the plastic dust down the sink. The last thing the world needs is more microplastics in the water. Use a paper towel and surface cleaner to clean them off as you sand, and definitely wear a mask.
This is a very interesting way to DIY a ground glass, thanks for sharing!
dachshunds are the best! Thank you for making these very informative vids!
Thanks for the compliment, we love our long, skinny little noodle dogs!
Flipped my phone two or three times before I realized what was going on in the intro shot.🤦🏻
Ever wonder why they cut the corners off the ground glass? It's so you can check for vignetting. If you look the the corner cut out, you should see the lens as round. If it's not round, your lens is not covering the film with an even light.
Admittedly, I didn't learn this until I'd been shooting large format for five years.
I always thought it was to provide a passage for air to flow when focusing the bellows so you don’t risk cracking the GG.
Hey Mat,
is it advisable to change an old groundglass (in my case mid 60s I think) to a newer one? Are they for example brighter/sharper?
Only just recently discovered your channel through Nicos Photography Channel. Keep up the good work!
Hi thanks for the question! There are newer ground glass options that are made for brighter viewing but they can get expensive. The easiest upgrade for viewing that won't hit the wallet as hard would be using a magnifier/fresnel on the back of the ground glass during focusing.
Hi Mat! Thanks a lot for the videos. Are amazing, keep doing in it!
I have some questions... I have a Fresnel screen installed on a Linhof 4x5 camera. I am wondering about scratching the Fresnel lens or the GG. It's common to scratch while using the loupe on your glass, either the Fresnel or the GG? It is a good idea to put something in the loupe for avoid scratching the glass?. And, which is the best advice to clean a Fresnel screen?.
Thank you Mat!
Hey David thanks for the comment! Since fresnel lenses are plastic, they are more prone to scratching than the ground glass. The ground side of the glass is the part you don't want scratched, but where the loupe is placed is on the "smooth" side so there's little issue there. I've never tried cleaning a fresnel, but I'd imagine you'd want to be cautious and use a non-abrasive cleaner and a microfiber cloth.
@@MatMarrash Thanks for the answer Mat! I appreciate your work on TH-cam. I think those kind of channels where you guys share all this knowledge for free to us it’s just amazing. And also I think this kind of content gives a human vision to photography which is very important. The renaissance of the analog photography is because this. Keep doing this amazing work and I will still learning happily. :)
Hey, Matt loves the channel learning so so much. Can getting a quality piece of ground glass make a big difference in image and focus? I have an Intrepid 4x5 and I'm guessing the ground glass is cheap.
A high quality ground glass can make a big difference, but pricing on quality scales dramatically. IMO adding a fresnel is an inexpensive way to improve viewing experience without spending several hundred bucks.
Thanks for the crazy quick answer. I have a fresnel i bought for my camera. Just getting back into LF after 20 years away, buying all the gear, I'm loving it, keep up the good work Matt.
Any tips on how to add grids to your ground glass?
My ground glass is plain with no grids and I really need to align things with grids coz I tend to exaggerate the perspective corrections especially for architectural works, most my building shots look top heavy due to too much back tilt... gridded ground glass for my linhof super technika is very rare and too expensive ... I tried to add pencil lines to the mat side of my ground glass but these lines look a little bit unparalleled and not so great .... BTW your channel is really resonates with me and I really appreciate and like your great videos looking forward to them every friday....cheers, Nick
Hey Nick, thanks for the question! My first view camera had a ground glass with a grid of permanent marker dots for reference. Others will use a thin plastic overlay to form opaque lines and the fanciest ones will use a tape-like material to fill in the ground glass making the lines transparent.
I’ve heard you mention before, but I’ve forgotten, why do some GG have clipped corners?
It helps you check the corners and to see if your working aperture will cover all parts of the image. If you can't see the full circle from the corner, chances are you're clipping off part of your image.
Hello Mat.
There are two sides to a Fresnell screen. A smooth and the circular cut side. Which side faces the lens when you mount it in front or behind the ground glass, or does it matter? Thanks. By the way, nice haircut :)
Hi Wayne great question! I believe in the lens side installations the circular cut side faces the lens much like the matte finish side of a ground glass. When using a page magnifier or add-on fresnel, you'll place the circles on the ground glass.
i want the Fresnel glass only for enlarge my face
when you working in the studio the setback of upside down back side left whatever it is will slow you down your work flow will suffer
It's surprisingly easy to get used to. Reflex viewers are available, but IMO pretty expensive unless the camera is bolted down in the studio.
Great video! I have the question in my mind for a long time. Fresnels can reduce vignetting on the focus screen when composing/focusing, but will there be vignetting on the actual film?
Thanks for the question. Once the film holder is inserted it is displacing the ground glass and fresnel, so any aspects present from the lens such as a vignette will still be recorded by the film.
@@MatMarrash So it's common to have vignette on large format photos?
@@yuchending4977 vignetting is a result of running out of image circle with your large format lens. This can happen by using a lens designed for a smaller format or by applying excess camera movements.
@@MatMarrash Sorry, I shouldn't use the term vignetting. Without fresnel lens, the center of the focus screen is brighter and the corners are darker. By using fresnel lens, the brightness is more uniforn across the focus screen. When place the film holder and shoot the actual film, will the actual film looks like focus screen without fresnel lens, that it's brighter in the center and darker in the corners?
@@yuchending4977 it's all up to the design and image circle of the lens used. More modern, corrected lenses will be very even, while older glass may have lots of falloff. Definitely recommend researching individual lenses to match your desired format and look.
Hi Mat, does frenel lens mounted on “photographer” side change the actual focus being an extra layer and not on film plane ?
The ground glass on the lens side catches most of light at the right distance, ( the image you actually see) the fresnel is just showing that image with better lighting
I could use some help. I bought a Speed Graflex and a 90mm 6.8 graflex optar wa lens. The graflex lens board doesn't fit the graflex and the film backs I bought are dont fit either even tho Keh said they fit with graflex press cameras. Ps I have spring back model
I'll do my best to help. Shoot me a detailed message with some quick reference photos to: largeformatquestions@gmail.com
@@MatMarrash thanks so much. I sent you a email
Doesn't the ground glass have to be of exact thickness for the focus to register in the same place as the film sitting in a holder? How loose can you be with the tolerance? The one Allen Ross made for you seem to be thicker than usual ground glass. Were there any focus issues?
No focus issues that I've noticed. The ground part of the glass is always facing towards the lens, and from what I can tell the only difference the thickness will make is how much it displaces the springs holding it to the frame.
Your "glass protector" is much more expensive than your ground glass, lol
As well a spare could be a simple and cheap etched frame glass.
Sinar accessories can definitely add up, making the DIY solutions all the more alluring. Thanks for the comment!
will the fresnel distort the image as you compose and focus?
Hey that's a great question! I've not noticed anything when using a fresnel lens with a normal or longer focal length lens. I've read that there can be issues when using a fresnel with a super wide angle lens. The only other thing that happens when focusing with a fresnel is if you're using a high magnification loupe, you'll see the ridges of plastic that make up the lens (some users find this annoying).
Mat, how do you get the ground surface on acrylic?
Hey Christopher, I believe it was a 200 - 300 grit sandpaper that provided the "ground" surface.
@@MatMarrash Thanks, Mat!
I don't think I can trust a Large Format Evangelist whose hair is less than 4" tall.
The greatest test of a relationship is how well we handle change. ;)
Tape it until you make it 😆
can you please help me? i have a speed graphic, i had to clean the ground glass and fresnel. they are nice and clean now but i forgot the order they go back in and what i am reading is not helping me. read this "Graflok backs made by Graflex Inc. for Graphic cameras' ground glasses sit on bosses on the focusing panel casting. Graflex Inc. intended their fresnels to sit between the GG and the lens. Graflok backs' focusing panels made by Graflex Inc. for Graphic cameras and intended to be used with Graflex' own fresnels have lower bosses than focusing panels made to be used without a fresnel" can you please tell me the order that my ground glass and fresnel goes back in, and what direction please? please?
Sure thing! With the camera's lens facing away from you, add the fresnel lens first, followed by the ground glass.
@@MatMarrash both pieces of glass have 2 sides, which way should they face? please?
@@dr.crazysdallekstudio8585 You'll want to position the grooved side of the fresnel towards the lens, and the rough/ground side of the ground glass also towards the lens.
@@MatMarrash again i have a speed graphic, you are suggesting this for a (Graflok backs made by Graflex Inc. for Graphic cameras')? but the speed graphic manual says ("c. Assemble Ektalite screen (6) and ground glass focusing screen (5) so that the grooved side of Ektalite screen is in contact with frosted side of ground glass screen: Polished side of ground glass screen will be on the outside facing the lens". so i am really confused, i have been told other positions for the GG and the Fresnel which by the way graphic calls an "Ektalite screen ". graphics' config according to the manual is the only way to get the focused image to coincide with the film plane. thanks anyway?
@@dr.crazysdallekstudio8585 The best thing I can recommend is perform a sharpness test to see which way works for your camera. You can use a ruler positioned at 45 degrees to check: www.bobatkins.com/photography/technical/focus_testing.html
Never say always, ha. A lot of large format view cameras have the fresnel on the outside, but on some cameras made by Arca Swiss, Linhof and others, including some medium format cameras, may have the fresnel on the lens side. The important thing is having the focusing side of the ground glass in the exact same position as the film plane of the film holders. This is a bit of nit picking perhaps. I'm just saying that it doesn't always go on the outside.
Hey Steve thanks for the comment. I briefly mentioned the two types, so I'm in agreement that they don't always have to go on the outside of the ground glass. When dealing with fresnels, you've got it 100%, make sure that you're not displacing that film plane or there could be focusing issues.
@@MatMarrash I guess I missed you mentioning both. The outside is the best way, according to some. They say that on the inside the fresnel will change the focus very slightly. Then others say that it's not enough to matter. On some medium format cameras it seems easier to spot sharp focus without a fresnel. Maybe the smaller viewfinder has something to do with that?
@@Stevewd1 I've heard varying accounts as well. The thing that turned me off of inside fresnels was that it limits the range of lenses able to be used. It may be related to the focusing issue you mentioned.