How T-Stops Compare to F-Stops: Is One Better Than the Other?

You may have heard of t-stops before, but what exactly are they and why do only some lenses use them?

In this video, Gerald Undone explains how to calculate f-stops and t-stops, as well as how they are relevant to each other. Interestingly, while they can seem very similar on the surface and even have number values that are alike, their application and usefulness don't exactly overlap.

T-stops are much more common in filmmaking than photography because matching the exact exposure between multiple lenses used in a scene creates harmony. In photography, this kind of perfect exposure matching is usually not greatly important looking at one still image and moving to the next. One is not really better or worse than the other, but each has their purpose to assist the creator with what needs to be accomplished. In exchange for not knowing the specific light transmittance in a regular photography lens, the f-stop number does give a better understanding of depth of field.

As the video explains, f-stop and t-stop numbers are fairly alike, and that gives an added bonus to using t-stops since one can usually guess the equivalent f-stop number from it. But guessing the t-stop from just the f-stop number is not possible without testing to find the light transmittance.

For a more detailed look at f-stops, watch his previous video.

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Joe Black's picture

Great share. Thank you

Pedro Pulido's picture

might be a bit of an underserved critique... but, i feel like a big majority of articles shared by fstoppers are now videos. I guess i might be alone in this, but to be really honest, i sometimes just want to read a bit about photography while at work and opening up videos isn't really doable with people around me. Ps. I'm my own boss, i can say this. The idea is to not upset other people working in the same office.

Yes, i could use headphones, etc... but my complaint is also about too many videos and sometimes, it's nice to just read someone's opinion in a well written article.

so to conclude, it would be really nice to have more written articles. But then again, i might be alone in this.

Agree on having more written content rather than videos.

Ryan Mense's picture

No worries, thanks for the feedback.

I think in general Fstoppers pushes out a lot more content than most places because we do it all and a bunch of it every day; original text articles and reviews, news, and video sharing. So it might seem like there's an overload of videos, but there's also a lot of written goodies too.

I have two suggestions that might help with your work issue. First is to bookmark the dedicated Originals-only URL because a large majority of that will be written content:
And second, know that on the front page every article that has a video inside it will have a play icon in the top left of its thumbnail, so that's how you can know before wasting time clicking in to something you can't watch at work. Hope that can help! 😊

Pedro Pulido's picture

Ladies and Gentleman, Mr. Ryan Mense didn't give a flying Fu.. to the fact that I wrote a critique in his article, even though I didn't even bother to really read it all or pay any attention to the video.
He answered with proper useful help and was very positive about my post.
This is what I call "a proper answer to constructive criticism" even though I did not "complain" in the right channel/post.

Hat's off to your very useful answer Ryan, and thank you for being positive and patient. This is how everyone should deal with criticism! thank you! And thanks for the useful tips! I'll be following them.

Ansel Spear's picture

I absolutely agree. Nothing about the workplace, but I simply want to absorb content at my own nuance-free pace.

I largely agree but I think Gerald Undone's content is always pretty great so any way he gets more exposure is fine by me.

Ansel Spear's picture

Maybe so, but reading mercifully isn't preceded by a 'catchy' must-have ident. Yuk!

That I can live with. YouTubers who have hyper-energetic or melodramatic personalities are exhausting and embarrassing to watch.

Pham Anh's picture

Same idea with me. I prefer reading as well.

Since most cameras can shoot video really well, this might become more important. I love T-stops because it will give you a clear indication of the brightness of the lens while F-stops remain somewhat vague.
One F2,8 lens might be brighter than another.

Another two cents for more articles with simple written content. Videos can sometimes be helpful, but mostly they waste time. Anyway, you always provide a link to the video so the reader can go there if interested.

Ansel Spear's picture

Great idea. The trouble with that is that someone's got to write the article in the first place. I fear those skills are fast dwindling amongst the Fstoppers staffers.