Max zoom range of T2i with Tamron 18-270mm vs Canon 55-250mm

[linkseer]

Just purchaced a new Tamron AF18-270mm lens. I also have a Canon EF-S 55-250mm.

I'm hoping someone can tell me why the Tamron zoom range at 270mm appears shorter than the Canon at 250mm.

I've done several tests mith my T2i mounted on a tripod and each lens set at its maximum zoom.

In every test the image produced using the Canon is noticeable closer to the subject.
Not exactly what I was expecting to see.

 

[Legion5]

Just purchaced a new Tamron AF18-270mm lens. I also have a Canon EF-S 55-250mm.

I'm hoping someone can tell me why the Tamron zoom range at 270mm appears shorter than the Canon at 250mm.

I've done several tests mith my T2i mounted on a tripod and each lens set at its maximum zoom.

In every test the image produced using the Canon is noticeable closer to the subject.
Not exactly what I was expecting to see.

What you're seeing is a combination of two issues.

The zoom rating is only at the maximum focal distance, this is true of any lens. Secondly to exaggerate zoom claims manufacturers allow lenses to extend their optical elements past their intended design. Your lens was likely designed as a 18-250mm with a minimum focal distance zoom of 200mm, they then let the zoom extend past 250mm to 270mm.

This design trick is often done to ridiculous superzooms to increase their marketability. The 55-250mm is a zoom lens that was not artificially extended.

An example of this issue is the 100-400mm Canon, near minimum focal distance the Canon 100-400 zooms to only 240mm when set to 400mm.

The problem with extending a zoom lens is that the image quality degrades by definition at least as much as cropping so the additional zoom is absolutely useless.

 

[iland]

It is a known marketing issue , yes , but of ...Canon
The lens that has a bad range is not the Tamron 18-270 but the Canon 55-250 .

If you'll perform the same test at 55mm you'll find Tamron much wider than Canon . If you'll perform one more test , you'll find that Canon's 75mm is equivalent with Tamron at 55mm .

I think that the reason behind it was that for Canon was easily to call the "Canon 75-270" lens as "Canon 55-250" because a better magnification factor (X4.5 vs X3.6 ) but mostly because they needed to show this lens as a continuation of the 18-55 kit lens and not as a continuation of the kit lens minus the 55-75 mm range which is practically missing from the 55-250 lens .

 

[aVolanche]

It is a known marketing issue , yes , but of ...Canon
The lens that has a bad range is not the Tamron 18-270 but the Canon 55-250 .

If you'll perform the same test at 55mm you'll find Tamron much wider than Canon . If you'll perform one more test , you'll find that Canon's 75mm is equivalent with Tamron at 55mm .

I think that the reason behind it was that for Canon was easily to call the "Canon 75-270" lens as "Canon 55-250" because a better magnification factor (X4.5 vs X3.6 ) but mostly because they needed to show this lens as a continuation of the 18-55 kit lens and not as a continuation of the kit lens minus the 55-75 mm range which is practically missing from the 55-250 lens .

This is worth a look.What you said might be untrue.It's a commonly known fact that superzooms tend to exaggerate their focal lengths.

http://www.juzaphoto.com/eng/articles/canon_18-200_sigma18-250_tamrom18-250_18-270.htm

 

[Legion5]

Zoom lens manufacturers are not likely to claim their products have zoom ranges which they cannot fulfill otherwise they'd be opening themselves to class action lawsuits. It's more likely that the zooms can fulfill their obligations at some combination of focal distance and zoom in some lab test, it's just that realistically these ratings are a joke.

 

[aVolanche]

Zoom lens manufacturers are not likely to claim their products have zoom ranges which they cannot fulfill otherwise they'd be opening themselves to class action lawsuits. It's more likely that the zooms can fulfill their obligations at some combination of focal distance and zoom in some lab test, it's just that realistically these ratings are a joke.

It's actually because the Tamron is an internally focusing lens and they measure the maximum focal length at infinity rather than at MFD.It causes the image to image to be less than 270mm at shorter distances than when focused to infinity.They play games with the method versus normal useage,as do all wide to long tele lens makers.

 

[linkseer]

Just wanted to say thank you to everyone who has responded.
I appreciate you all for taking time to address my question and
share your knowledge.

 

[Legion5]

Zoom lens manufacturers are not likely to claim their products have zoom ranges which they cannot fulfill otherwise they'd be opening themselves to class action lawsuits. It's more likely that the zooms can fulfill their obligations at some combination of focal distance and zoom in some lab test, it's just that realistically these ratings are a joke.

It's actually because the Tamron is an internally focusing lens and they measure the maximum focal length at infinity rather than at MFD.It causes the image to image to be less than 270mm at shorter distances than when focused to infinity.They play games with the method versus normal useage,as do all wide to long tele lens makers.

I'm not disagreeing that's probably how it's rated, it's a lab test as opposed to a real world test.

 

[PhilPreston3072]

Here's a quote from http://www.the-digital-picture.com/Reviews/Canon-EF-S-18-200mm-f-3.5-5.6-IS-Lens-Review.aspx comparing the Canon 18-200IS and Canon EF 200 F2.8:

The 18-200 is 87% as far away when framing this subject size - making its 200mm seem more like 174mm at its longest setting at this moderate distance. /

So even from the same manufacturer they don't agree.

 

[aVolanche]

Here's a quote from http://www.the-digital-picture.com/Reviews/Canon-EF-S-18-200mm-f-3.5-5.6-IS-Lens-Review.aspx comparing the Canon 18-200IS and Canon EF 200 F2.8:

The 18-200 is 87% as far away when framing this subject size - making its 200mm seem more like 174mm at its longest setting at this moderate distance. /

So even from the same manufacturer they don't agree.

It's not really that they disagree(same manufacturer) but that they "massage" the numbers by using a different set of criteria.Notice that the 2 different primes(both 200mm,but different max apertures) are almost identical distances from the framed subject,but the 18-200mm needs to be much closer to frame the same image(all 3 lenses at the 200mm FL).

 

[dfw1417]

Just like the 3 accountants answered the question during an interview. The final question of the interview was: What is 1 + 1 equal to?

The 1st 2 accountants said 2 and did not get the job.

The 3rd accountant after pausing for a moment said " What do you want it to be equal to?

Needless to say accountant 3 got the job!!!

 

[TOTO89]

Hi,

Today, i bought the Tamron Lenses 18-270, as the first post said the tamron lenses appears to be smaller when set up as the same range with the canon.

I do different try at 70 and 200, both set up, on tripod to be sure and the canon seems always to give a bigger zoom.

I just read the last post, does it mean according to what you say it is better to have different lenses at different range rather than a "all-in-one" lenses?

Though, I ask this question but that true it looks clear for me it better to get different lenses to get the higher zoom. (though, hard to admit this after spent a lot of money in that lenses to discover this problem, why I have been so blind .... )
I still have the invoice, I might be able to change it against another one =D