Very helpful. And if I understand what you are saying on such a technical topic, than that proves you are an excellent instructor. Thanks.

@DustinAbbottTWI

2 жыл бұрын

That's kind, thank you.

Good presentation and very helpful

@DustinAbbottTWI

2 жыл бұрын

Glad you liked it

Mr. A as always very useful information, I tend to follow the second part of your advice and always rent before I buy a lens, so I can look at 100 images in varying light conditions. I have made 2 or 3 purchases after seeing some reviewers not rate a lens so high. I have also found if I am going to use a particular lens to photograph people, sharpness can be overrated. Between yourself and that fella Roger over at Lens rentals I find you both to be spot on in your assessments. A week with a rental and I have enough to decide if its a good fit for me.

@DustinAbbottTWI

2 жыл бұрын

Thanks for the nice feedback, and it sounds to me like you have a smart system for making an informed decision for yourself.

@bddt3268

Жыл бұрын

wrong info

@bddt3268

Жыл бұрын

Read the notes: *8 is Radial value, not resolution value; #9 is Tangential value, not contractual value. If you don't understand the meaning of MTF chart, please shut up, don't misleading others.

Very Interesting, thanks for the new knowledge I gained!

@DustinAbbottTWI

2 жыл бұрын

My pleasure!

A correction: the solid and dotted lines show radial and tangential mtf respectively. Mtf is a combination of both sharpness and contrast. Radial and tangential refer to the direction of the line pairs, whether they are segments of lines originating from the centre of the image (radial) or at right angles to those (tangential). The difference in mtf between these two is astigmatism.

@DustinAbbottTWI

2 жыл бұрын

That is technically correct, but too complex an explanation for this kind of an application. I'm trying to help people understand MTF on a basic (practical level), not bury them in complexities...which defeats the purpose.

@TripleJAu

2 жыл бұрын

@@DustinAbbottTWI I for one greatly appreciate it 🙂

@Bayonet1809

2 жыл бұрын

@@DustinAbbottTWI A reasonable aim to be sure, but there is a difference between simplification and providing wrong information. The fact that mtf charts actually show both the amount and the field dependent location of astigmatism would be lost on an unaware viewer who would finish watching your video thinking the different lines represented sharpness and contrast. To simplify correctly you could have instead said to average the lines to get an approximation of resolution.

One also has to be careful when reading mtf charts, especially in Sony's at f/8, not to forget that manufacturers will often not consider diffraction in their calculations (and yes, most mtf charts are calculated rather than tested, except those from Zeiss and Leica). The consequence of this is that the Sony lenses at f/8 are not as sharp as their mtf would lead you to believe.

@DustinAbbottTWI

2 жыл бұрын

I think that is overselling the impact of diffraction at F8. Even a 50MP camera sensor is just starting to see the effects of diffraction at F8 (F6.7 is the diffraction point for the Alpha 1), so the impact is extremely minimal.

@Bayonet1809

2 жыл бұрын

@@DustinAbbottTWI If you want to see an example of diffraction's impact at moderate apertures in mtf charts then look up the datasheet for the Leica APO-Summicron-SL 35/2. Notice how the mtf is higher wide open at f/2 than stopped down to f/5.6, let alone f/8. This is because Leica actually takes diffraction into account in their charts, unlike Sony, Canon, et al.

@bobsykes

2 жыл бұрын

The comment is absolutely correct. Hasselblad also provides measured MTF charts which reflect diffraction, along with Leica and Zeiss as stated below. Using the XCD 45mm f/4 P lens I can easily see the reduction in contrast and especially micro contrast at f/8 as compared to wide open at f/4.

Really helpful thanks!

@DustinAbbottTWI

Жыл бұрын

Glad it helped!

"Modulation Transfer Function or "MTF" is a measurement of the optical performance potential of a lens. ... A MTF chart plots the contrast and resolution of a lens from the center to its edges against a "perfect" lens that would transmit 100% of the light that passes through it."

@DustinAbbottTWI

2 жыл бұрын

I do think that its time to see the 50 lines pair standard introduced, as a lot of lenses are charting pretty close to the "perfect" standard at 30 LP

Very interesting video and great conclusion. . Some manufacturers present MTF with higher frequencies than 30. It is important to pay attention to this when comparing lenses from different manufacturers. Most of the available charts are wide open. Stopping down by one stop can change the things.

@DustinAbbottTWI

2 жыл бұрын

I've seen very, very few MTF charts at higher lp/mm rates that don't include 30.

@metphmet

2 жыл бұрын

@@DustinAbbottTWI For example Zeiss gives 10,20 and 40

Really helpful and good knowledge! Thanks Dustin!

@DustinAbbottTWI

2 жыл бұрын

Glad it was helpful!

Thanks for a very useful, simplified explanation of MTF charts. Whilst I had some understanding, this really cemented it for me. Well done!!

@DustinAbbottTWI

2 жыл бұрын

Glad it was helpful!

@bddt3268

Жыл бұрын

Read the notes: *8 is Radial value, not resolution value; #9 is Tangential value, not contractual value. If you don't understand the meaning of MTF chart, please shut up, don't misleading others.

One of your best!

@DustinAbbottTWI

2 жыл бұрын

Thank you

Great video Dustin. Very easy to understand...simple and plain.

@DustinAbbottTWI

2 жыл бұрын

Glad it was helpful!

You just missed out on doing with Fujifilm MTF charts that I find hard to read and interestingly had a 15 and 45lines/mm charts with sagittal and méridional lines (that honestly got me confused). I think Sony is doing a great job making it simple. Thanks for the educational video and I hope you'll get to review Fujifilm new 23 and 33mm 1.4 in a near future.

@DustinAbbottTWI

2 жыл бұрын

I do plan to review the new Fuji's when I get a chance.

@bddt3268

Жыл бұрын

Read the notes: *8 is Radial value, not resolution value; #9 is Tangential value, not contractual value. If you don't understand the meaning of MTF chart, please shut up, don't misleading others.

When people talk about a lens being about to "resolve" a camera's resolution. What exactly are they talking about? Who knows if they will make an adapter for it, or if I'd actually do it, but if I wanted to adapt E mount lenses to GFX 100s Camera. How can I go about seeing if a lens will "resolve".

@DustinAbbottTWI

7 ай бұрын

As resolution climbs the flaws of any lens are exposed as those flaws cover more pixels. Just about any lens looks pretty good at 20MP or so, but as resolution climbs many lenses start to look softer. The most demanding at the moment is Fuji's 40MP APS-C sensor, which is actually like the equivalent of a over 90MP on full frame and over 150MP on medium format.

Thanks a lot Dustin, this was really interesting! Did not know about the contrast lines at all.

@DustinAbbottTWI

2 жыл бұрын

I'm glad I helped out. That's not the technical name for the dotted line, but that is the real world outcome.

I love the info here but i cant get pass how sharp this video looks. Please what camera and lens was used here. I subscribed just for that alone.

@DustinAbbottTWI

2 жыл бұрын

Sony Alpha 1 and 135mm F1.8 GM - kind of hard to beat that combo!

@ILaxative

2 жыл бұрын

@@DustinAbbottTWI lol wow. I might dump my c300 mkiii and get it 😂

Enjoyable and informative Dustin! Thanks!

@DustinAbbottTWI

2 жыл бұрын

Glad you enjoyed it!

I hope that more manufactures of Lenses will show MTF of 50lp/mm and more and show at least 3 different apertures, full aperture, 2 and 4 stops, fx 2.0 4.0 and 8.0, a forth showing the best aperture setting will be very nice.

@DustinAbbottTWI

2 жыл бұрын

I do agree that it's time to move to a higher standard that is more representative of where today's lenses and sensors are.

@aliendroneservices6621

2 жыл бұрын

There's still manufacturing variance, so you need to test your own copy of the lens.

@cameraprepper7938

2 жыл бұрын

@@aliendroneservices6621 Only in cheap Lenses, not much in better quality Lenses !

@DustinAbbottTWI

2 жыл бұрын

@alien - I agree, but that only helps if you understand the baseline of MTF to have a reasonable expectation of performance.

Very useful! Always nice to learn something new!

@DustinAbbottTWI

2 жыл бұрын

Glad it was helpful!

Very useful. Thanks, Dustin! Do you have plans to review the new TAMRON 18-300mm F/3.5-6.3Di III-A VC VXD? I was excited for that as an all-in-one travel lens, but reviews have started coming out in Japan and it doesn't look so great. I can't understand Japanese but the MTF chart explains a lot. :D

@DustinAbbottTWI

2 жыл бұрын

I'm expecting one soon for review.

@Zunidrap

2 жыл бұрын

@@DustinAbbottTWI That's really good news!

Amazing tutorial brother I really appreciate it . wow 🤩

@DustinAbbottTWI

2 жыл бұрын

My pleasure

So useful!

@DustinAbbottTWI

2 жыл бұрын

Glad you think so!

Thanks a lot!

@DustinAbbottTWI

2 жыл бұрын

You're welcome!

Very helpful. Thank you

@DustinAbbottTWI

2 жыл бұрын

You're welcome!

A useful and informative video Dustin, thanks for sharing. I understand it's a very simplified overview of the data presented but gives a better understanding on how to read them now.

@DustinAbbottTWI

2 жыл бұрын

Glad it was helpful!

@bddt3268

Жыл бұрын

Read the notes: *8 is Radial value, not resolution value; #9 is Tangential value, not contractual value. If you don't understand the meaning of MTF chart, please shut up, don't misleading others.

@plutonium5156

9 ай бұрын

​@@bddt3268if you can't spell correctly, please shut up

Excellent explanation. love it.

@DustinAbbottTWI

2 жыл бұрын

Glad it was helpful!

Finally I understand how to read MTF charts. Thank you, Dustin

@DustinAbbottTWI

2 жыл бұрын

Mission accomplished.

@bddt3268

Жыл бұрын

Read the notes: *8 is Radial value, not resolution value; #9 is Tangential value, not contractual value. If you don't understand the meaning of MTF chart, please shut up, don't misleading others.

Well done, very useful, thanks

@DustinAbbottTWI

2 жыл бұрын

You are welcome!

Very helpful! Just wondering the MTF carts can be used cross brands and compared as well? Is this testing standardised trough different brands?

@DustinAbbottTWI

Жыл бұрын

Yes and no. Not every manufacturer does the same lines per mm, so you need to watch for that. The most common combination is 10 l/mm and 30 l/mm, though Fuji uses 15 l/mm and 45 l/mm, and I've seen as high as 50 l/mm from some. I mostly disregard the 10 or 15 l/mm figures, as that assumes a much lower resolution point than modern cameras. The 30 l/mm is more relevant. Essentially the higher the l/mm rating, the more demanding the MTF chart as it assumes a higher resolution. If you mentally account for these variances, you can make a decent cross brand comparison.

@marleenvandam6931

Жыл бұрын

@@DustinAbbottTWI Thanks for great work!

MTF charts were the KZread lens review videos of the 20th century. I remember that was basically the ONLY stats that you got in the 1980s.

@DustinAbbottTWI

2 жыл бұрын

LOL - I'm glad that has improved!

Check out the GM 400mm f2.8. The MTF chart shows a perfect score

@DustinAbbottTWI

2 жыл бұрын

That is a stunningly good lens.

Great information! Is there any way to relate these tables to these new sensors with 40, 50, 100 mp?

@DustinAbbottTWI

2 жыл бұрын

Hi David, I do think that they should update to a 50 lines/pair standard, but in the meantime you can extrapolate somewhat from the difference between the 10 lp/mm and 30 lp/mm. Carry that on, and you can at least make an educated guess. My experience in real world use, though, is that a sharp lens will at least appear even sharper on a high resolution body. A good lens is a good lens, period.

Thanks a lot for the video. Overall, it was extremely useful. I think some parts of the video can be a bit confusing for technically minded people. I don't know if anybody brought it up, but the converging lines (sagittal and meridional) means less astigmatism, thus it causes increase in contrast as a result as well as more balanced background blur. Maybe you could mention astigmatism, anybody who uses glasses would know the term. To be fair, if you make it more technical you could lose some of the audience. Even lens manufacturers do no not properly explain what these lines mean, and they often lack proper legends (i.e. Canon charts).

@DustinAbbottTWI

2 жыл бұрын

I debated getting into astigmatism, but settled on just using the terms sharpness and contrast for simplicity sake.

Thank you 🙏

@DustinAbbottTWI

2 жыл бұрын

You’re welcome 😊

Your explanation of what the dotted and solid lines are is not really correct as far as I understand it: As described in the footnote, it is the distinction between sagittal and meridional image plane, which also is why the curves always start at the same value since sagittal and meridional are the same on-axis(google "sagittal vs meridional" to get visuals on what that means). Therefore, a difference between solid and dashed curves indicates different resolution in light rays following those planes in the imaging system and the difference is then manifested in aberrations like astigmatism or a similar non-symmetric aberrations. Also, contrary to what you said, both curves indicate a contrast as the y-axis represents the contrast of a feature of the corresponding resolution (10 or 30 LP/mm)...

@DustinAbbottTWI

3 ай бұрын

You may have missed the point of this video: it is to show the practical application of MTF charts as it relates to real world performance. I look at the MTF charts for hundreds of lenses as a part of my reviews, and practically they function in the way that I have described...which I verify through real world tests.

Super informative.

@DustinAbbottTWI

2 жыл бұрын

Glad it was helpful!

You talk about lines per mm (sigma) and line PAIRS per mm (Sony). That is a factor of 2 difference! I’m confused now 😬 But thanks for your great reviews!

@DustinAbbottTWI

2 жыл бұрын

It's line pairs for both.

Thanks for the interesting video Dustin, it seems that lens performance is getting better and better…not really related to this, do you have any news from kamlan? I am enjoying quite a lot their 21mm 1.8 on fuji, but it seems that they haven’t released the 32mm which they had announced in February, I hope this is only due to the COVID and that the company is doing well, I also wish that they make other 1.4/1.8 lenses….

@DustinAbbottTWI

2 жыл бұрын

I had a bit of a bad experience with Kamlan on a business level, and it has (unfortunately) soured our relationship. I haven't heard from them since the release of the 50mm F1.0 II

@paololarocca7684

2 жыл бұрын

sorry to hear that...

Lens designer here. Some of this explanation is wrong. At 7:07 minutes: the dotted lines are not “contrast”. The solid and dotted lines are sagittal and meridional NOT resolution and contrast. Green lines are 30 cycles and red are 10. You can call those contrast and resolution respectively.

@DustinAbbottTWI

2 жыл бұрын

Using the terms sagittal and meridional are not really relevant to your average audience, so you always have to find the balance between the technical and relevant in this type of forum. I don’t think that I specifically said that the solid and dotted lines WERE resolution and contrast, though I did say that the distance between them is a reliable indicator of contrast.

Big thanks! Now I have an idea...

@DustinAbbottTWI

2 жыл бұрын

Glad I could help!

So, new Tamron 28-75 G2 will be sharp as hell!

@DustinAbbottTWI

2 жыл бұрын

That's very true.

Great bokeh in the opening scene. Creamy background. What lens?

@DustinAbbottTWI

2 жыл бұрын

Sony Alpha 1 with Sony 135mm F1.8 G Master. A pricy combo, unfortunately!

👍

@DustinAbbottTWI

2 жыл бұрын

Thanks!

Love your videos Mr. Abbott, but what you explain an MTF chart showing and what it's actually showing (particularly with the Sony charts) is not correct.

@DustinAbbottTWI

2 жыл бұрын

Care to be more specific?

Read the notes: *8 is Radial value, not resolution value; #9 is Tangential value, not contractual value. If you don't understand the meaning of MTF chart, please shut up, don't misleading others.

@DustinAbbottTWI

Жыл бұрын

Yes, you've cleared things up for everyone. I do understand exactly what you are saying, and I do know how to read MTF charts, but I'm trying to make that knowledge more accessible to the tens of thousand of photographers who don't understand them. Radial, tangential, and contractual are not words that are going to help that cause.

4:44 Wow! Dustin, you're not even close when comparing 10 lp/mm and 30 lp/mm to the resoultion of R6 and R5. Sorry to say it, but now it's obvious - you completly don't understand these units. Please, re-educate yourself in this area before you want educate others. Let me know if you need help or clarification.

@DustinAbbottTWI

2 жыл бұрын

I'm speaking in broad strokes here to simplify things for those who don't understand MTF charts at all. The truth of the matter is that manufacturers should probably move to a 50lp/mm standard to better reflect modern lens capabilities.

2 жыл бұрын

@@DustinAbbottTWI 30 lp/mm is still enough to compare lenses. But you're wright... Manufacturers should move to 50 lp/mm or even 60 lp/mm.

@DustinAbbottTWI

2 жыл бұрын

Agreed.

@kistovisback

2 жыл бұрын

Try again, maybe you weren't condescending enough :)

@longrider9551

2 жыл бұрын

@@kistovisback A sure sign Mr. A is at the top of the trusted lens reviewers, the pseudo experts who know everything except how to create something beautiful start to show up. They spend all day spanning the forums to show us how smart they are. They fail to realize the easiest form of knowledge to acquire is to regurgitate someone else's original thought . When they start quoting from Leica and Hasselblad forums you know they also got sucked in by the marketing of those cameras companies that sell you a lifestyle more than a camera. Folks wearing scarfs and writing in fountain pens while sipping expresso in a sidewalk café are very powerful motivators to a certain segment of the population. Once they bite on the religion they have to then justify their superiority by looking down their nose at the common folk who just shoot weddings and their dogs. Mr. A you have my respect and are one of only 2 channels I agreed to support as a patron, Thank You for all your fine work Mr. A, your an A+ in my book