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05-28-2012, 03:33 PM   #1
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crop factor

Hi i'm trying to get into doing real estate photos and i need a wide angle lens. I'm thinking about the DA 15mm limited but i'm not sure if it if formated correctly for APS-C sensors. I want to make sure it is because if not then it winds up being 22.5mm which wouldn't even be wider than the standard 18-55 kit lens. I tried asking this on answers.yahoo.com but got very mixed answers. Can anyone help me?

05-28-2012, 04:58 PM   #2
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The first thing you need to do is forget you ever heard the term "crop factor".

A 15mm lens is a 15mm lens no matter the size of the sensor. The DA series lenses are designed to cover an APS-C sensor.

Crop factor - Wikipedia, the free encyclopedia
05-28-2012, 05:01 PM   #3
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Second that. Forget about "crop factor".

So yes, 15 is wider than 18. And if you get the DA 12-24, you can go wider still. Sigma 10-20, and Tamron 10-24 are also available.
05-28-2012, 05:44 PM   #4
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Yes, forget about crop factor.

Focal length is a physical property of the lens. It never changes. What changes is the field of view depending on the size of the sensor/film. In other words, if you must think in terms of crop factor, then crop factor is a function of sensor size, not focal length.

05-28-2012, 06:25 PM   #5
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As has been said, a lens doesn't magically change its length when moved to another camera. A smaller frame sees less of the projected image, is all -- it crops the image, hence the "crap factor". If you are an old 35mm film shooter and you're just starting to a dSLR, it can help you visualize the differences between projections. Otherwise, forget about it!

For real estate photos, wider is better. Many people are happy with a Sigma 10-20 -- once they get a good copy. I really like my Tamron 10-24. I chose it instead of the Sigmas or the Pentax 12-24 because of focal range, image quality, price, warranty, and quality control. Whatever lens you get, be sure the seller has a no-questions return+refund policy, so you won't be stuck with a lens that doesn't work for you. Good luck!
05-28-2012, 06:36 PM   #6
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QuoteOriginally posted by shaolen Quote
I want to make sure it is because if not then it winds up being 22.5mm which wouldn't even be wider than the standard 18-55 kit lens.
Not sure I follow your logic on this. If you are trying to calculate the field of view in 35mm terms, then you need to do the same on the 18-55 as well, which gives you 27-82.

But as noted above, you should not be doing that. 15mm is 15mm, it is a physical property of the lens and cannot change no matter what camera you attach.

Wide angle on 35mm film (or full frame digital) is considered to be in the 24 - 28mm range, with 15-20 being ultra wide angle. Wide angle on Aps-c is considered to be 15-20mm. And UWA is maybe 10 to 14mm. All of that is subjective and others may have a different set of numbers but it is a good rule of thumb. I have never done real estate photos so I'm not sure what field of view you are looking for but I would think a zoom would be better suited to this than a fixed focal length, sometimes you are limited to where you can stand. Or maybe I misunderstood what real estate photography is.

QuoteOriginally posted by shaolen Quote
asking this on answers.yahoo.com but got very mixed answers.
Yes, I am sure you did get a wide variety of answers there.
05-28-2012, 06:47 PM   #7
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I don't have any real estate experience, but I'd think you'd want at least a 10mm, if not the 8mm sigma. There's a huge difference in every mm at the wide end.

Paul
05-28-2012, 06:49 PM   #8
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QuoteOriginally posted by RioRico Quote
For real estate photos, wider is better.
Yes and no... It's important that the image be faithful to the scale of the space. If the purchaser walks into a room and thinks... "Hey, the photos make this place look larger than it really is." Your seller (client) has a credibility problem that you helped create. Objections like that are very difficult to overcome. As such, it might be better to show less than more.

Cheers... M

05-28-2012, 06:57 PM   #9
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QuoteOriginally posted by shaolen Quote
I'm thinking about the DA 15mm limited
I think for real estate photos you might want something a bit wider, as rooms tend to be square (ie 90 degree corners) and the DA 15 has a horizontal field of view of 77 degrees you might find it a little limiting if trying to get as much of a room in as possible. As mentioned some of the super wide angle zooms might be more suitable for your purpose. They will give you that bit of extra flexibility that you will probably need.

QuoteOriginally posted by Michaelina2 Quote
Yes and no... It's important that the image be faithful to the scale of the space. If the purchaser walks into a room and thinks... "Hey, the photos make this place look larger than it really is." Your seller (client) has a credibility problem that you helped create. Objections like that are very difficult to overcome. As such, it might be better to show less than more.
This may be true in some instances, but I think the idea of the advertisement is to get the people there in the first place. Be it by a deceptive method or not. As a real-estate photog you want to make the place look as warm and inviting as possible (assuming residential properties anyway)
05-28-2012, 07:02 PM   #10
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QuoteOriginally posted by Michaelina2 Quote
QuoteOriginally posted by RioRico:
For real estate photos, wider is better.
Yes and no... It's important that the image be faithful to the scale of the space. If the purchaser walks into a room and thinks... "Hey, the photos make this place look larger than it really is." Your seller (client) has a credibility problem that you helped create. Objections like that are very difficult to overcome. As such, it might be better to show less than more.
OK, I'll amend that: The CAPABILITY of wider, is better. An ultrawide shot *may* be necessary to show the extent of a small space. I wouldn't shoot every room at 8mm rectilinear. Human 2-eyes vision is about equivalent to 12mm rectilinear on APS-C. That may be one reason Pentax's UWA is 12-24. But being able to go wider can help in some situations. OK?
05-28-2012, 07:13 PM   #11
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HA! Every house/apartment interior shot I have ever looked at (in a listing) makes the rooms look much bigger. That's pretty standard.
05-28-2012, 08:24 PM   #12
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QuoteOriginally posted by Michaelina2 Quote
Yes and no... It's important that the image be faithful to the scale of the space. If the purchaser walks into a room and thinks... "Hey, the photos make this place look larger than it really is." Your seller (client) has a credibility problem that you helped create. Objections like that are very difficult to overcome. As such, it might be better to show less than more.

Cheers... M
Have you had real estate agents say this? I'm guessing the objective of the photos is usually to generate interest, and the agent would rather have a live prospect who was encouraged to inquire based on the most favorable possible presentation of the space. If they don't get the client in the door they can't use their sale skills to overcome objections, upsell, or otherwise make a sale.

Paul
05-29-2012, 11:52 AM   #13
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do the ultra wide angle lenses fisheye at the wide end?
05-29-2012, 12:18 PM   #14
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QuoteOriginally posted by shaolen Quote
do the ultra wide angle lenses fisheye at the wide end?
No, Although there is some distortion at the wide end it is not "fish-eye" that is a different type of lens. Pentax has the 10-17 FE and there are others available if you want fish-eye.

Adam has just posted a complete in depth review of the ultra wide lenses available for Pentax, very timely for you! Here is the link to the reviews.
05-29-2012, 01:30 PM   #15
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QuoteOriginally posted by shaolen Quote
Hi i'm trying to get into doing real estate photos and i need a wide angle lens. I'm thinking about the DA 15mm limited but i'm not sure if it if formated correctly for APS-C sensors. I want to make sure it is because if not then it winds up being 22.5mm which wouldn't even be wider than the standard 18-55 kit lens. I tried asking this on answers.yahoo.com but got very mixed answers. Can anyone help me?
As mentioned by many others, the DA15 is in fact wider than 18-55 kit lens. I have used my 15mm limited for my personal house hunting, but I think I would need something wider for professional results, or to stitch together multiple photos. The UWA zooms would probably come in more handy.
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