Upgrading lenses on a D90 to EF level

[peteck18]

Hi all,

I shoot with a d90.  I upgraded from a rebel, so most fo my lenses are EF-S.  I want to get better glass and am a little confused about the issue of using an EF lens on my camera.  I understand that there is a 1.6x crop factor, so a 50mm would really be closer to an 80mm on my camera (right?).  So here's my question.  Eventually I'll want to upgrade to a full frame, so I figure I should start upgrading my lenses to EF level so that when I buy the next camera, I'll have the lenses, spreading out the financial pain, as it were.  Does this make sense? On the other hand, I've read that using EF lenses on an APS-C is less than ideal.  What do you all think?

Thanks!

Peter

[kvbarkley]

A 50mm EF-S lens will have the same field of view as a 50 mm EF lens.

There is no reason not to use an EF lens on an EF-S mount. I have several.

[peteck18]

So...I'm now more than a little confused. I've read that a 100 mm would behave like a 160mm. Please help me understand. I've been searching for explanations of how this works.

[cicopo]

That has nothing to do with the lens. It's because the sensor in the camera is smaller so there is a magnification factor due to that. The same lens performs the same on a crop body & full frame body but the smaller sensor changes the field of view to look like you've zoomed in tighter.

[rs-eos · Accepted solution]

Here's an image taken with a 50mm lens on a full-frame camera.  I then applied the 1.6 crop on what would happen if using that same 50mm on a crop-sensor camera (same shooting location).  I lightened the areas around the crop.

As stated above, the lens is still the same focal length.  It would have the same distortions/compression effects*

* On a crop-sensor camera with an EF lens, the outer edges of the lens would not contribute at all; you're using just the center area.  So any distortions or other effects around the edges of such a lens (e.g. softness) on a full-frame would not be there (or be far less) when on a crop-sensor camera. 

Other notes:

This 50mm would have the field of view of an 80mm lens on the crop-sensor.  With full-frame gear, I could of course crop my images in post to achieve the same 80mm angle-of-view.  However, the images in my case would go from 30 MP down to 12 MP due to the crop.   One advantage of the crop-camera bodies is that you often get 20 MP plus.   Thus, even though you're not zoomed in any more than what the 50mm gives you, you'd end up with more pixels on the crop-camera for this particular example.

There's a downside though too... if you want to have extremely wide angles of view, you're better off with a full-frame camera with those wide EF lenses as you get no cropping.   So a 14mm gives a 14mm angle of view.  On a crop-sensor camera, that lens would be less field of view of around 22mm.

[Waddizzle]

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@peteck18 wrote:
So...I'm now more than a little confused. I've read that a 100 mm would behave like a 160mm. Please help me understand. I've been searching for explanations of how this works.

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[Lotus7]

To expand a little on the Image Circle graphic Waddizzle posted you might read this basic article on angle of view:

https://www.thephotovideoguy.ca/blog/focal-length-and-angle-of-view

The simple explanation is that a smaller sensor size provides a narrower angle of view for any given focal length lens.  That narrower angle of view is equivalent to a longer focal length lens.  That equivalent focal length ratio is commonly called the  "crop factor".  That's why an iPhone [tiny image sensor] with a 4 mm lens can have the same angle of view as a full frame camera with a 26 mm lens. It has an "crop factor" of about 6.5.

[Tronhard]

Try this article:
https://www.dpreview.com/articles/2666934640/what-is-equivalence-and-why-should-i-care

or my own article on this, shared via a MS OneDrive link:

Equivalence 

[cicopo]

So you know you should have a 90D because a D90 is a Nikon camera and there is absolutely no reasons that an EF lens won't perform properly on your 90D. The most important rule of this is you get what you pay for meaning there are low end consumer grade lenses & there are high end pro level lenses (L series usually quality as pro level) so when shopping & pick what fits your needs but not just by price.

[peteck18]

Oops!  Meant 90D.   Sorry about that!!!!!