EF 70-210 f4.0 - True Focal Length when used with APS-C Camera?

[trossit]

Hello Forum, I have a question regarding the Canon EF 70-210 f4.0 I recently purchased.  This lens was manufactured in 1987 designed for 35mm cameras.  When this lens is used with APS-C sensor DSLR (30D) what wouild be the atucal adjusted focal length?  Is it an actually increase in magnificatin os just more of a cropped image?

Thanks,

TR

[Tronhard]

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@ebiggs1 wrote:

Bravo! Thorough explanation.

"Take the EF-S 17-55, awesome good lens!"

That might be a stretch, Threvor.

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Now, Ernie my friend, I AM surprised at you!   I have seen you laud the 17-55 quite a few times, and as I wrote that I actually thought of  you! LOL!!!

You are correct, of course... it is getting on a bit now, and in the absolute pecking order of lenses it is not hugely high on the list, like many of the later units. Still for someone with an APS-C camera it ranks as one of the better walk-around lenses there is IMHO for its low constand f/2.8 aperture.  I would also put one of my favourites - the 15-85 IS USM, but that has a variable aperture and I thought you would prize the constant f/2.8 above that, and the 55-250 STM,  plus the 18-135 STM and later USM versions, are up there too - they are actually among my favourites.

Still, my other comments hold water, I believe.   The glass in APS-C lenses is not inherently inferior to that of many APS-C lenses - other build factors might be: like metal and weather resistant construction.   Like any range, there are some better than others, of course.

Thanks for your support on the explanation.  I honestly think they need to change the conversation of focal length and bring in the term FoV insteal of FL to describe the result of the combination of lens and sensor, even if they simply used the equivalent FL and called it the true FoV that would be an improvement.  Lord knows it confuses a lot of users.

[ebiggs1]

"Now, Ernie my friend, I AM surprised at you!"

Apologies my friend. I had a senior moment . I was thinking 18-55mm kit lens. The EF-S 17-55mm f/2.8 IS USM Lens is a great lens. It is one of a few lenses that makes me wish I still had a corp body camera. I had six Rebels (not all at the same time) a while back when I was still working.

" I honestly think they need to change the conversation of focal length and bring in the term FoV insteal of FL ..."

Preaching to the choir there. I have said that from day one.

"...  there are some better than others, of course."

And you seem to be able to pull the best from. Almost makes me hesitant to criticize any of them. And to be totally honest it is build quality that I don't like about them most of all. Way back I made the decision to not buy any more because they just  didn't hold up like "L" series do. When you are in this business full time your gear becomes tools. And such are treated like tools. They do a job!  When you are an amateur or enthusiast they are your babies and you take great care of them.

Sometimes I still hear a 90D calling me to take it home.  

[Tronhard]

Ha! I can SO relate!!! I still enjoy shooting with my Rebels - they do a great job. I was shooting with my 21y.o. D30 a few days ago and it still performs well.

I must admit I AM enjoying shooting with my R6 and the new RF lenses too. The new tech is fantastic for animal photography - the animal eye tracking is amazing, and the IBIS + lens IS are a great combo in the RF lenses. 

Now Canon, just release an R7 please!!!!!  And while you're at it, perhaps a FF throwback MILC to remind me of what it was like to shoot with the Canon A-1 (but with all the latest tech under the hood, like Nikon did with the Nikon Df).

[trossit]

Thanks Trevor....this is great!!

[jrhoffman75]

What they might be alluding to is that current Rebels and X0D cameras come with kit lenses that are actually designated EF-S. They are not usable on 35mm film Canon cameras or full frame DSLRs.

A secondary issue is that while the older EF lenses are usable on current digital cameras, full frame or crop, the modern lenses have better resolving power. The high pixel (30MP and above) cameras have higher resolving power than film, any lens deficiencies are revealed. When Canon released the high MP 5Ds body they published a list of recommended lenses (and by omission non-recommended lenses.)

[trossit]

Hello John,

You had mentioned to me that you once owned the 30D and if I had any questions to ask.  I have been testing this body, which was in like new condition for about 2 weeks and only noticed one strange behavior and it couild be normal.  Is it normal for the built in flash to flicker as you half depress the shutter release?  Its acts like a red-eye reduction function but the red-eye is turn OFF in the menu screen.  The flash flickers about 3-4 times before firing.  Did your 30D do anything like this?

Thanks,

Tom

[jrhoffman75]

Hi Tom. You must have misunderstood my post. I never owned a 30D.

Perhaps the flash is acting as a focus assist light. What are your shooting conditions? Indoors/low light?

[jrhoffman75]

Check Custom Function CFn-05