55-250 IS vs 70-300 IS MTF

[Jeff Greenberg]

Is it correct that MTF, besides being in chart form, converts to a number with 5.0 being optically perfect?

According to current info, what will be worst mm/f-stop combo for 55-250mm IS & how bad will it be compared to the worst settings possible for my newest lens, the 17-55mm f2.8 IS?

Will I notice significant difference in optical quality between the above two lenses when used on 40Ds? What about the two head to head at 55mm & same f-stops?

Advice appreciated.

FYI, Canon had to replace IS motor on my 17-55mm.

Regards, JG

 

[caterpillar]

Is it correct that MTF, besides being in chart form, converts to a
number with 5.0 being optically perfect?

I don't know about 5.0 being the perfect score. I am talking about Canon's published MTF charts and it is 1.0 as the perfect score. According for them a 0.6 is a good score and a 0.8 is excellent for resolution. Contrast is different. I have my book borrowed so I can't check exactly, but that's what I recall it was written there.

According to current info, what will be worst mm/f-stop combo for
55-250mm IS & how bad will it be compared to the worst settings
possible for my newest lens, the 17-55mm f2.8 IS?

I don't know why or how you can compare a 17-55 and 55-250. Maybe you meant only up to 55mm as that is the only valid comparison in focal length. If you try to match performance of the 17-55 at 17mm vs at 200mm for the 55-250 IS, it would be meaningless to draw up any conclusions.

Besides, what is worst for one lens is the best readings for another. And even one's "worst" performance is already excellent or very good by any standards. Take for example the 135f2L. At f2.8 match that with the 70-200 f2.8L and it would put the zoom to a mild embarrassment. But it isn't that the 70-200 at 135mm is a slouch either. Match that output and scale it to a 55-200 mk2 (f5.6) and the latter will be put to shame by the L lens. That is the L's not best performance for all apertures too. And yet, that same 55-200 will put to shame a 100-300 lens at the same aperture and focal length.

Will I notice significant difference in optical quality between the
above two lenses when used on 40Ds? What about the two head to head
at 55mm & same f-stops?

Now you made me work! I have to do a web search. Unfortunately, I can't bring up the japanese web site with the mtf of the 55-250 anymore. So, only from memory I will compared.

Ok, Only at 55mm, your 17-55 is sharper at the center up to 8mm where they are now equal. But by 12-15mm, the 17-55 at 55mm isn't so great. This is where the 55-250 is better. It holds the sharpness up to the corners.

Will you notice this differences? I doubt it, especially if you are using it for portraiture. If you were shooting landscape, the 55-250 will have the edge even if the 17-55 is sharper at the center. Why? because those corners are going to stand up while the 17-55 at 55 will falter. Stopping it down to f8 helps, and it will help a lot. The 55-250 is still better though its rez, if I recall is not as high 0.9 at the center for you 17-55 at 55 vs 0.8 to my memory of the 55-250 at 55mm. Contrast will hardly be signifcant as both will be contrasty.

One thing about the 55-250 IS is that it's S and M lines don't break apart greatly even to the edges, unlike the 17-55 at 55mm. And it doesn't fall precipituously like the 17-55 at 55mm. This means, even if the latter is sharper in the center, the 55-250 will have more perceived sharpness especially at the edges simply because the S and M lines don't spread out apart. In short, the 55-250 is more consistent all throught the image and predicatable in sharpness as if it was a prime. In fact, it is behaves similarly as the 70-200 f4L IS more than the 70-300 IS.

Again, if you are shooting tight portraits, you would not notice the difference between the two except maybe if you print very, very big or pixel peep. But even then it's not going to be a big difference, except in the corners where the 55-250 is better. But would you notice that if in normal portraiture you want that OOF in the first place? So, only landscape will notice it. But then again, you normally stop down to f8-11 for these iamges, so again, the 17-55 disadvantage at the corners is lessened greatly when you stop down. The verdict? They are about the same.

Now, think about it, at f4 maybe up to 100mm where it will stay at f4, wouldn't you love to have that sharp of a lens similar to a prime or the 70-200 f4L IS? And to pay for it for around U$350 instead of U$1,000 for the 70-200 f4L IS? Even at 55mm, have a decent f4 for U$350 vs the 17-55's U$1,000 price tag? I have a 100 f2 usm, and if the MTF holds, it means, it is very sharp and close to my prime! Of course I lose the f2-3.5 aperture of the prime. But I do gain a 55-250 zoom with optical performance very near the primes or the best L lens!

This is why I am getting a tamron 17-50 f2.8 di-2 (instead of your 17-55 IS). Together with the 55-250 IS, I will have a formidable sharp lineup whose limitations don't bother me anyway (ef-s, plastic mount, no ring usm, no ftm, not as well built, etc). The 10-22 and the 24-105L will round it up when I need wide or a more all around lens. If I need lens speed, I go for my primes. But as you can see, I can mix and match without spending too much for a 70-200L. The 55-250's IS, sharpness, size, weight, cost, black color makes up for it's weaknesses for me (I say for me only ).

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• Caterpillar

'Always in the process of changing, growing, and transforming.'

 

[Jeff Greenberg]

This is why I am getting a tamron 17-50 f2.8 di-2 (instead of your 17-55 IS).

Because of price or because of optical quality or both? Does that Tamron have IS? Is there tele-extender for 55-250mm IS? Physically impossible? Would you be interested in sample RAW file (or portion) from my 17-55mm f2.8 IS to verify your MTF conclusions? Specifically mine because it was recently adjusted by Canon Jamesburg for edge-to-edge sharpness. It failed first adjustment while there & was held extra day for 2nd adjustment. This makes me curious about whether it could now be better than average for its model...?
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Regards, JG

 

[loafer]

MTF charts are nice - but focus accuracy and focus speed are more important features to look for in lenses. That is the big difference between the tamron 17-50 and canon 17-55. No one knows how the 55-250 will compare to anything else I can only guess that it will be similar to the 70-300 IS but worse than the 70-200 L varieties available. I think the 55-250 will put the 70-300 DO IS in a coffin.

 

[caterpillar]

This is why I am getting a tamron 17-50 f2.8 di-2 (instead of your 17-55 IS).

Because of price or because of optical quality or both? Does that
Tamron have IS?

No IS. But at 17mm to maybe 40mm, even 50mm, I won't miss IS that much. Optically, the tamron 17-50 is spoken with the same recognition as the 17-55 IS. And it only costs U$450 or whereabouts.

Is there tele-extender for 55-250mm IS? Physically
impossible?

You can't use those TCs from Canon with this lens. But I think 3rd parties can be used with it, not sure though. Personally, I am not thinking of the 55-250 IS as something I need to add a 1.4x TC. As it is, it is very versatile already. I'd bring my 100-400 IS if I needed range. But then again, the reason for this lens is not to reach 300-400mm. The reason for this lens is to have a portable but useful 50-250mm range lens (w/c is equivalent to an 88-400mm really).

Would you be interested in sample RAW file (or portion)
from my 17-55mm f2.8 IS to verify your MTF conclusions?

I don't need to. And what I wrote was not a conclusion. Afer all we are all looking at MTFs. And I don't have the chart (non-bar graph) MTF of the tamron.

Specifically
mine because it was recently adjusted by Canon Jamesburg for
edge-to-edge sharpness. It failed first adjustment while there & was
held extra day for 2nd adjustment. This makes me curious about
whether it could now be better than average for its model...?

We can't help these variants. I had to get my 24-105L caibrated and now it is very good. That is the nature of this whole business unfortunately This is why I will be testing the 17-50 I will be getting next week by bringing my 24-105L and my 17-35 f2.8-4 tamron with a notebook before I buy it.

What we can rely though is that we do know the MTF and at least I am familiar with reading it and more or less translating it to real world shooting. So, I am aware of what it should deliver when i do test it.
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• Caterpillar

'Always in the process of changing, growing, and transforming.'

 

[caterpillar]

MTF charts are nice - but focus accuracy and focus speed are more
important features to look for in lenses. That is the big difference
between the tamron 17-50 and canon 17-55.

Not necessarily, specially for focus speed. People forget that there is at least 50 years when there was no AF. Sharpness and optical performance is primary for most general photography. AF is a recent feature and though you can put that feature set first in some situations, in most cases it must be 2nd or 3rd in priority. Ponder then why nobody asks for the ef 100-300 ring usm lens. It focuses fast, and it is accurate. Cheap too. But people ask for the 70-300 IS, or even way before, the 75-300 IS. Why is that? The reason is simple. Optically it was bad. Not to mention, it had no IS. Focus speed and accuracy takes a back seat for this lens.

Take for example the noted tamron 28-75. No wedding or events shooter ever complained that its AF is "slow" that it missed the shot. I have used two Di tamrons for 2.5 years in shooting events, and I didn't think they were slow. Mind you, I was using a 300d and the slow AFing D60. these cameras were not the 10d or 20ds w/c had better AF focusing points.

"Slow" is relative. If I were shooting fast action, then my defunct 28-75 di is slow. In fact, some birders consider the 100-400L slow in AF, considering that has ring usm already.

No one knows how the
55-250 will compare to anything else I can only guess that it will
be similar to the 70-300 IS but worse than the 70-200 L varieties
available. I think the 55-250 will put the 70-300 DO IS in a coffin.

In build, probably lesser than the 70-300 Is. AF speed, likely the same. IS perfromance, likely the same. But opticall qualities, I think the 55-250 is much better than the 70-300 IS based on the MTFs. Actually, the 55-250 IS' MTF is similar to the good ef 55-200 mk2. Execpt it is 0.1 better.

Now if only we can see some sample shots of that lens!

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• Caterpillar

'Always in the process of changing, growing, and transforming.'

 

[loafer]

With the tiny viewfinders on 1.6 crop dslr it is basically impossible to hand focus. In addition many people evaluate the results at a much larger magnification than a 35 mm negative enlarged to a 4x6 print - i.e. pixel peepers.

 

[Montana500]

MTF charts are nice - but focus accuracy and focus speed are more
important features to look for in lenses. That is the big difference
between the tamron 17-50 and canon 17-55. No one knows how the
55-250 will compare to anything else I can only guess that it will
be similar to the 70-300 IS but worse than the 70-200 L varieties
available. I think the 55-250 will put the 70-300 DO IS in a coffin.

the kit lens focuses very well, so I wouldn't be too worried about using this new 55-250IS for landscapes (sports and action might be another story).

If this lens is as sharp as the MTF indicates, I may pick one up along with a 300F4 IS.

 

[Jeff Greenberg]

I have the latter. Am I going to notice drop in IQ according to the MTFs if I switch to former for the IS & lower weight?
--
Regards, JG

 

[Doug Kerr]

n/t

 

[caterpillar]

I have the latter. Am I going to notice drop in IQ according to the
MTFs if I switch to former for the IS & lower weight?
--

JG,

I still can't access the japanese site, so I am working on memory here. I do have the 35-350L on my Lenswork III book, so I can see the mtf there. Based on this, the 35-350L gets beaten decisively on all focal lengths, even stopped down. The 28-300 IS is much better, and except on corners, may be closer.

If you have access to the 35-350L mtf the easiest way to compare it to the 55-250 IS, even if we don't have the 55-250 IS mtf charts anymore, iis to look at the ef 55-200 mk2 lens. It is very similar in curve and S & M position, you'd think you are looking at the same lens. Except that the ef-s 55-250 IS is .1 better and the contrast is far off from the 55-200 mk2. That 0.1 is significant especially if the S & M lines basically stick together up to the corners. The 35-350 is not playing in the same league in terms of MTF performance.

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• Caterpillar

'Always in the process of changing, growing, and transforming.'

 

[Jeff Greenberg]

Will the Japanese 55-250 IS MTF be EXACTLY same as US market 55-250 IS MTF?
--
Regards, JG

 

[jpr2]

70-300 IS is an option for those who want decent quality and black color
i like 70-200f/4, but i strongly don't want white lenses

SAME here (about white), also i'm constantly using 70-300IS - close to a year now,
and it shines in every situation (except in not so good light and @300mm),

and would have jumped for 70-200/4 IS long ago, if... NOT for it being white;
luckily (for me) recently have secured a BLACK copy of a 300/4L IS, which
fulfills, and sometimes exceeds (esp. with 1.4x TC, when it is also vereeeery
good) my hunger for a relatively LIGHTWEIGHT short tele - all this is sort of
obvious to many here, but not to Canon, so... i'm voicing these sentiments
in a sort of vain hope that they finally invest a little in a additional line
that paints some of them BLACK too (, as it is pretty often voiced at
many places!!!

jpr2

 

[Magne Nilsen]

Hi,

I know I am late to this thread... but I just wanted to add a little;

I rescaled the MTFs to make them more comparable.

While I do not expect wonders, it sure looks promising. Having used both the two others, I know their pros and cons. Still; coupled with a 400D/XTi this should make for a great lightweight kit, which often is the most important thing - to me... So - I just ordered the 55-250, they expect delivery on Oct 3rd, locally...



~~~~
Magne

MTFs from here:
http://cweb.canon.jp/ef/lineup/ef-s/ef-s55-250-f4-56is/index.html

 

[bvphotos]

I don't know to read MTF charts, but how does the 55-250's chart compare with the Sigma 18-200 OS's?

Also, are MTFs a reasonable representation of how the lens works in real life, or are they simply theoretical models?

--
http://bvphotos.smugmug.com
Rebel XT, Tamron 24-135, Canon 100 f2, Canon 50 1.8, kit lens

 

[travelinbri]

Wanna follow this, a lightweight 55-250 IS would be better for me then the heavier 70-300 IS, as I prefer it has some more on the wide end, and be lighter for travel...

 

[Magne Nilsen]

I don't know to read MTF charts, but how does the 55-250's chart
compare with the Sigma 18-200 OS's?

See below - similar, but I think the 55-250 has the edge...

Also, are MTFs a reasonable representation of how the lens works in
real life, or are they simply theoretical models?

They inform you about resolving power and contrast, but not much about i.e. colors, and nothing about focus speed and handling.
More MTF info here:

http://www.luminous-landscape.com/tutorials/understanding-series/understanding-mtf.shtml



~~~~
Magne

 

[caterpillar]

I don't know to read MTF charts, but how does the 55-250's chart
compare with the Sigma 18-200 OS's?

See below - similar, but I think the 55-250 has the edge...

Also, are MTFs a reasonable representation of how the lens works in
real life, or are they simply theoretical models?

They inform you about resolving power and contrast, but not much
about i.e. colors, and nothing about focus speed and handling.
More MTF info here:

http://www.luminous-landscape.com/tutorials/understanding-series/understanding-mtf.shtml

Here's the 70-200 f4L IS for comparison:

at 70mm:



at 200mm:



It is very hard to compare it to the sigma 18-200 because the chart we are looking at is the 18mm vs the 55mm. It's too far off and it would be unfair to match them. However, the sigma seems to have a decent if not good mtf on 18. It's not bad at all.

At 200mm and 250mm, the 55-250 beats the sigma, not just by a little. Yes, there is a 50mm difference but that is not as big now at the long end. Plus the sigma is f6.3 while the 55-250 is f5.6, so stop it down a little and it adds up a tad to the better performance. But regardless, the sigma does not hold up at 200mm . Canon is much better. Again, in fairness, the sigma is an 18-200 lens, and there are a lot of compromises there.

Now, for the interesting part.

As you can see the ef-s 55-250 IS is better compared to the 70-200 f4L IS. Remember to read the 70-200 only up to the 15mm mark as the ef-s is for crop cameras. The L lens beats the ef-s lens at 200/250mm in both contrast and sharpness. But the ef-s holds its own and will be fairly sharp, especially at the center where they are very close.

At the wide end, the comparison becomes interesting. We don't have a 70mm take on the ef-s lens, but if we assume that it is the same (likely it is the same, THOUGH I suspect there the mtf will be slightly better at 70 for the efs) the ef-s lens actually is better than the 70-200L lens! Yes, the L is slightly higher, but it's M line falls of and parts off with the S line. The ef-s lens, however, holds it there and therefore is actually sharper! At f8, the L lens pulls in even with the ef-s, but of course, you will likely be using these lenses wide open or just slightly stopped down due to the need to maintain shutter speed.

As far as contrast goes, the L is slightly ahead, but it is negligible in real world situations. In fact, the ef-s is slightly better in contrast at the edges at f8. But as I said, it is negligible in real world situations.

I suspect that if you use the 55-250 up to around 180mm only, the MTF will be very close to the 70-200L lens. Actually, the ef-s is beaten only at the corners, so you can safely go to 200-250mm if the corners/edges isn't that much of a problem to you. In tight portraits, most likely it won't. But if it is, just remind yourself to keep your shots at around 150-180mm max. Think of the lens as a 55-150/180 lens and the rest is bonus. It keeps your wide open aperture also within f4.5-5.0 most likely at those ranges.

I will no longer compare the 55-250 with the 70-300 IS because, the ef-s is really much better than the 70-300 IS as the charts will show.

Again, MTF don't say about flare, handling, AF speed, AF accuracy, color rendition, color saturation, or other issues. But it is obvious that the ef-s 55-250 is a sleeper lens, if only MTF charts will be the basis. If there are no problems with the lens, it will be one hell of a lens to own for its price and optical capabilities. If it lives up to its billing, it will be in line with the 10-22, 17-55, and 60 macro in terms of sharpness. In fact, as the MTF charts show, it seems to be playing in the same league as the 70-200 f4L IS. I doubt that it will have the same color or saturation though. But as far as sharpness and contrast goes, it is up there with that lens.

--
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• Caterpillar

'Always in the process of changing, growing, and transforming.'

 

[caterpillar]

Will the Japanese 55-250 IS MTF be EXACTLY same as US market 55-250
IS MTF?
--
Regards, JG

First, we don't know if the 55-250 IS will be released in the USA. In Asia and Europe , it seems so.

2ndly, MTF results aren't fixed and we expect it to be the same for all those coming out of the factory. There are sample variations. So, that could affect it. In theory, and for most practical purposes, they should be the same or very close to the sample lens used. After all, they are there for the simple reason that a reviewer can find out a reasonable expectation as to how the lens will perform.

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• Caterpillar

'Always in the process of changing, growing, and transforming.'

 

[loafer]

Doubtful...

Lenses are available in all markets - there are a lot of people who will import to the US for the 'grey market'. Some of these like B&H stand by the import with a warrantee that is the equal of the manufacturer's. I can't imagine that you can't buy what you want in America --- at least in the photography equipment area.