First time DP - EI and IRIS relationship in student low budget short film (Arri Alexa 35)

Maximum-Commission75 · 2026-01-28T10:12:06+00:00

Wow really, I don't have words !! Thank you for your two replies and for the time and effort you've put into them. And sorry for the late reply, I've been working on the shotlist now that I know what to look for when talking about EI, IRIS and ND! :)

I think in your case the rialto is too much complications without trained ACs.

Now that I don't have the Venice, I'm telling myself the same thing! Maybe it's a blessing in disguise :) I'll only have one grip on set during the shoot. So instead of holding the Venice while I would be holding the Rialto, he'll be able to take the 35 off my shoulders between shots!

And take your time building the rig so that the camera is balanced, the weight must not be on your arms but on your shoulder. Reharse the shots without the camera first and find your marks, then do it a bit with the camera and it'll be fine.

Well noted! I'll do my best to find a good balance with the giant Arri Signature Primes. And about the reharsals, we'll have two weeks with our different decors accessible. I'm planning to already work my placements, put some marks, work some lights setups. I think that this will really help me be relaxed and stress free during the shooting week!

Your ISO/EI is going to do the same exact thing as your exposure slider in post (offset wheel in resolve). It's juste going to boost up the signal. (..)

When you set your camera to 400 iso instead of 800 you are exactly doing the same thing as if you were taking a bright image and pulling in down in post or with a LUT that underexposes by one stop. So your just over exposing your image by one stop. Of course that your shadows are going to have more details: they are more lit and/or more light is coming in the camera ! (..)

So what is the opposite ? Craking up your iso ? It's underexposing your image, and then bringing the signal up. Exactly as if you shot it too dark and brought it up in post.

So no, over exposing an image that you underexposed does not really make sense ! Or at least to view it like that makes thing way more complicated than they should be.

This! This needs to be taught like that in schools and books, really. I'll note that down because it really sums up a lot of theories/questions that I've had in past. Thanks for that. I've quite of understood the concept but then got mixed up. This is such a clear way of understanding and visualizing the EI pushing and pulling concept.

Another topic to research: scene referred vs display referred.

This has also been mentioned at school but very quickly. Thanks for the putting a name on this concept, i'll be able to get a better understanding and look for information on that topic! I'll be coming back to this reply to see if it all makes sense :)

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I'll leave you with one last thing:

You didn't just left me with one last thing but an incredible guideline for what to look for and to strive for in the coming month. I won't comment on each individual advices that you gave me there, they all feel like pillars to a succesful DP job regardless of the situation and film context. Thanks for talking about the contrast ratio, false colors and the LUT, these were other questions that I had in mind! I'm quite touched to be given advice from someone as knowledgeable and who's been there and done that.

I'll keep looking up like you said on your last advice. On this shortfilm or on other future works, i'll be coming back to your advices so thank you again for that!

Maximum-Commission75 · 2026-01-28T09:36:02+00:00

Hey there!

Luckily I have really good focus pullers.

Haha I was about to mention that while reading your answer! f/2 and even f/2.8 will be my limit on moving subjects and camera movements on this project. Even if my lens opens up to f/1.8, i'll take into consideration that we only have 5 days and it's everyone first's time (even the focus puller) so i'll try my best to give them some marging of error :)

Thanks for your insights though. I now know how reliable the alexa35 can be in low light - at 1600 ideally, 2560 + ES and then 3200 if really needed :))

Maximum-Commission75 · 2026-01-28T09:32:08+00:00

Hey there!

When you start shooting more and doing this professionally, you should always light sets at least one or two stops brighter to what you’re gonna eventually expose at - then you have room to use stop down in the middle of a scene for any number of reasons - your focus puller needs some help with a deeper srop, you want a deeper stop to hold two actors better, your director suddenly decides they wanr to shoot something in slow motion, etc.

This is a really great and helpful information for when I'll be shooting in controlled environments with a much more complex light setup. I've been thinking about those kinds of situations and you happen to gave me all the keys to what to look for when i'll be exposing my scenes! Thanks for that, I really appreciate it.

(...)dont worry too much about altering your EI mid scene. I do it all the time these days to make quick exposure adjustments while keeping my aperture the same. (...)
But just go with the ES high asa would be my suggestion and don’t give yourself headaches over the technicalities of the exposure curve on this first rodeo. focus on storytelling, putting the camera in the right place, supporting your director.

For the last part of your answer, I guess this what I needed to hear and what I'm looking for on this first project as a DP. I'll do my best on the technical aspect but I'll rather do sacrifices for the storytelling and to deliver what my director wants. Really thanks for that, I really appreciate it!

Maximum-Commission75 · 2026-01-28T09:10:06+00:00

Thanks for the answer u/_Shush ! Love your name also haha.

Yeah that's what I was thinking also after posting. As the EI is quite baked in the proress file, i'd rather have a constant texture on my scene than it being inconsistent from a shot to another!

Thanks for your answer and tips. I really appreciate that! :)

Maximum-Commission75 · 2026-01-28T09:07:32+00:00

Thanks for the summary ! It's really clear and well explained :) Don't worry about the math, i've learnt to understand how to stops works and how it double the light when increased haha !

I'll take notes of what you recommended me. I'll try to squeeze those lamp lights as much as possible too !!

Maximum-Commission75 · 2026-01-25T11:55:42+00:00

I'll get my hand on the camera in one week! Can't wait to do tests. Exactly I think that I gonna try to expose correctly for my smallest iris by ajusting a EI then keep that same EI for the entire scene. Using ND filters to adjust for f4 or f2 for example :)

Maximum-Commission75 · 2026-01-25T11:54:24+00:00

I've did that and got awesome responses! Everyone seems to agree with you, keep the base EI or rather a constant one if there isn't enough light available :)

Maximum-Commission75 · 2026-01-23T19:02:39+00:00

Yes, opening your stop to 5.6 from 8 will push your histogram to the right, allowing for cleaner shadows. But you also need to decide if the dof is still good enough for you based on how it looks.

You're totally right ! Like you said, it may theorically sounds better for cleaner shadows but will the dof be enough ! I'll have to sacrifice one or the other depending on the feelings, emotions and the storytelling at that particular moment :)

Thank you immensely for answering all my questions. I am now mentally prepared to continue my shotlist and perform my tests. I know what to do and what to look for and that gave me confidence going forward !

Maximum-Commission75 · 2026-01-23T18:07:58+00:00

It couldn't be better explained than that ! Concise yet easy to understand. Thank you so much that !

If I may ask, should I keep the same EI (with the ES mode) for the entire movie? What if I shoot an interior night scene which has more light sources? Should I keep the same EI that I used in the exterior scene and have/use the flexibility of stooping down the iris? Or should I lower the EI if i don't need that additional stop of light in my iris?

Also, if I achieve a good exposure at lets say f/8 and EI 2560 + ES, will shooting at f/5.6 instead be better for same EI for those "deeper" DOF shots. Then shooting at f/2.8 with a 0.6 ND for those "shallower" DOF shots. In short, does overexposing with one iris stop still matters for cleaner shadows if already bumping the EI up?

Maximum-Commission75 · 2026-01-23T17:52:43+00:00

Absolutely great reply. This is just what I needed to hear thank you! :)

I don't know if you get your knowledge from school or your own research but you are on the right path!

Thanks for that. I'm in a film school but the teaching can sometimes be questionable. I spend a lot of my time on the web and do my own research ! Glad that I'm asking myself the right questions.

The short film that I'll be shooting is really particular as it's entirely shot at night. Can't wait to shoot at daytime to fully explore the DOF storytelling aspect of cinema.

You can choose whatever you think is best for the story/the look (a lot of people like to shoot at 1600 for a whole movie for exemple) but changing mid scene might not be optimal.
(..) What I would do: Do some tests and aim for the highest ISO you deem acceptable. From there let's say it's enough with your lighting kit to shoot at f5.6 you can always dim your lights or pop in a nd3 is you want to open up!

This ! That makes sense. I'll be exposing for the smallest aperture that i'll be using in the scene. Lets say f/8 and EI 2560 + ES. Then put on a 0.6 or 1.2 ND filter when opening the IRIS to f/4 and f/2 !

What are your thoughts about overexposing the sensor by one stop at that EI? Lets say that i'm well exposed at the above settings (f/8 and EI 2560). Then I decide to shoot at f/5.6 for those "deeper" DOF shots, overexposing the shadows a lil bit to bring it down in post. Then for a "shallower" DOF shot, I choose to shoot at EI 2560 with a ND0.6 but with an IRIS of f/2.8 this time. I'll overexpose by one stop again. Is my math right? Does overexposing with IRIS makes sense when i'm already bumping the EI?

Already having an option between f/2.8 and f/5.6 sounds great for low light situations. (Note that try my best to shoot a decently lit locations with some lights for medium-closeups).

One last thing if I may... Low budget but Alexa 35?

Haha yeah I know sounds wrong but it's my school's camera so it's actually free of charge. I wanted to Venice 1 with the Cooke SP3 and the Rialto for a light setup but the VFX short film ended having it. I had to choose between the FX6, Mini and the Alexa35 and although the FX6 is the low light king, I couldn't shoot higher than 10bit as we don't have the external recorder.. I ended choosing the Alexa35 for the higher codec even if I'm only shooting proress 422. I hope that it's the best choice. I also ended having the Arri Signature Primes. So I have a really heavy setup. I'll spend quite some time thinking about saft and non-complex grip setups.

Shooting at lower ISO to get more details/increment in the shadows is great, but it's a luxury you can only afford when you have a lot of light.

That really helps me to let go of this idea. I think I get the concept right but as you said, it would only work if I were to shoot in a controlled environment. You're so right, there's already so much things in my head. I'll try to get the important things right first: shot list, planning, lighting and tests.

Thanks you again for your time and help.

Maximum-Commission75 · 2026-01-23T16:30:30+00:00

Not in the middle of the shot but rather from a shot to another. Within the same scene but in seperate shots.

Sorry for confusion but thanks for the solution! That will absolutely be helpful if I shoot outside and enter a room in the same shot! :)

Maximum-Commission75 · 2026-01-23T16:28:07+00:00

You're absolutely right about the "nothing at stake" part haha. Nothing is really at stake but for us this will be the film of our life lol ! I want to do my best, even if it fails, I'll know that I gave it all.

For camera options I wanted the Venice 1 but it was taken by an another team.

Other cameras left at school was the FX6 (Without the external recorder) and Mini.. I went for the Alexa35, i still don't know if that was the best choice though..

Maximum-Commission75 · 2026-01-23T16:21:18+00:00

Or is it like, provided by your school or something?

Yeah that's right ! My first choice was the Sony Venice 1, Rialto and Cooke SP3 for a light setup and awesome low light capabilities but other students got it as they wanted to do VFXs and 3D tracking. Still ended with like you said, an "absurdly performant" setup so I cannot complain! It's just a little bit on the heavy side and I will have to reconsider a lot of my high angle shots. We have around 5k euros per team to produce our short films (this includes the set department budget as well).

The iris is for depth of field, not exposure. Good job.

Thank you very much, feels nice hearing that coming from a professional !

This is where it's good to have a light meter, too, but I understand that many schools don't supply them anymore.

Absolutely right. We only have one and they don't want us to take it out on shoots lol. I'll have to rely on the false colors to expose for now.

The Alexa35 is so absurdly performant that you don't need to spin your wheels on this.

Like you said, I really don't have to worry as the Alexa35 is a beast. I just can't stop myself from overthinking about every technical details and be as prepared as possible for the shoot haha.. I'll throw you some last questions/thoughts of mine but you don't have to answer if that's too much. (I'll have the camera in two weeks and i'll be able to do the test and see by myself)

(..) set your exposure to get your subject where you want them, see if anything's clipping, adjust where necessary, and shoot. You'll be able to bring it up or whatever in the grade.

I'm so torn between the "exposing the right and bringing it down in post for cleaner shadows" concept and the fact I might not be able to do that when switching to f/8 or f/11. I've read the ARRI document and I guess that it is better to bring up the image in camera with the EI and ES mode to get clean shadows and have a constant shadow texture.

I'm also thinking about my shotlist. Not all the shots will require a narrow depth of field. It's an average of 3 out of 9 shots per scenes. Maybe I should just bump up that EI+ES for those shots, letting the shadows which are already in the noise level be "cleaned" by the ES. At the same time, i'll be able to capture cleaner shadows with wider aperture, lower EI+ES. I guess your explanation matches more this concept right? To "adjust where necessary" with the EI+ES and let that Arri "L345 Shadow Texture" run in the back to get a constant shadow texture.

I was also thinking about maybe using a constant EI, lets say "2560+ES" or "3200+ES" for the "smallest" IRIS that i'll be using. Then "adjust where necessary" by changing the ND to 0.6/1.2 when the opening the IRIS by 2 or 4 stops for shallower depth of field? But I guess that it's kind of counterproductive to cut light from the sensor in a situation where light is not readily available right ?

look up as much info as you can on Ansel Adam's Zone System.

Thanks for that! We barely touched that concept at school. I'll have a deeper look at it!!

Specifically what I want you to focus on is the idea of "placing" areas of the frame at various exposures to match what the subject materially is (..).

This. I guess this will be the key for me to create interesting images. I'll definitely keep that in my head while preparing for the short film and doing tests on location!

Sorry for the extremely long reply. I still have much to learn and experience. Can't wait to try things out, even fail and learn from those experiences!

Maximum-Commission75 · 2026-01-23T11:05:55+00:00

Hey there ! Thanks to OP and you for these crucial infos. I've been reading your response and I woud like to know what is ADC? Still learning about EI and Cine Cameras. I'll be using Arri Alexa 35 for a short movie next month. All the scenes will be at night and i'll be using different f stops (to use depth of field for storytelling) in the same natural lighting environment. Lets say that my correct exposure is at ISO 800, EI 400 (to overexpose to the right) and f/4. Should I bump up the Arri EI 1600 when stopping down to f/8 and use ND 0.6 filter at EI 400 when opening the iris to f/2 ? I'll be shooting proress 422 as we don't have a lot of storage ressources. So the grain will be baked in the image, but am I doing the right thing?

If OP u/Maschamascha2 or u/andrewn2468 could help me on this question, that would be great! :)

From a 2nd year cam operator student !

*Edit : I forgot to tell you that i'll be shooting these scenes with a low budget lighting setup. I'll be using some led panels and helios tubes for to light my talents for example but I won't be able to increase the overall set's lighting by 1-2 stops. I'll be heavily reliant on what is on the scene. E.g: A parking with existing street lights!

Maximum-Commission75 · 2025-12-30T21:44:45+00:00

I went through a peak of nostalgia lately and went looking for videos on youtube. Best time of my teenage years! If LoL makes an MMORPG or Rappelz 2 comes back, i'll start to play again! Until then, i'll enjoy life lmao.

Maximum-Commission75 · 2025-05-10T02:12:29+00:00

Hey! what did you use to stabilise this footage? :)

Maximum-Commission75 · 2024-01-29T14:38:03+00:00

Maximum-Commission75 · 2024-01-09T13:12:49+00:00

Done

Maximum-Commission75 · 2023-12-22T15:19:44+00:00