# TDP and LensRentals start sharing info...



## ahsanford (Jul 21, 2015)

This is promising news...

http://www.the-digital-picture.com/News/News-Post.aspx?News=15481

I imagine this forum's residents will make good use of this!

- A


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## bereninga (Jul 21, 2015)

Awesome news! Thanks to TDP and LensRentals for providing such a useful tool for the photo community.


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## AlanF (Jul 21, 2015)

Yes, but what we all want to know is whether our copy of the lens is a lemon at the bottom of the spread or a well above average at the top.


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## ahsanford (Jul 21, 2015)

AlanF said:


> Yes, but what we all want to know is whether our copy of the lens is a lemon at the bottom of the spread or a well above average at the top.



1) Roger hasn't started offering testing of YOUR lens on OLAF yet. But I imagine, as a business owner who has sunk a great of capital and sweat equity into that rig, he would be a fool not to. Do you know how many nutty forum-dwelling enthusiasts would pony up $50 maybe even $100 to see if they had a good copy of something? I really think that service will happen someday.

2) For now, at least we _have_ the variability data on this new page, even if it is only for wide open lens performance right now. That's still a lot more than what we had yesterday. 

- A


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## Bdube (Jul 21, 2015)

ahsanford said:


> AlanF said:
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> 
> > Yes, but what we all want to know is whether our copy of the lens is a lemon at the bottom of the spread or a well above average at the top.
> ...



These are tested on the ImageMaster, but the price would probably be north of that for a lens test, even with the level of automation I have implemented, because it ties up the machine for quite a while. 

We won't be doing variance for lenses as we stop them down for more than 1 or 2 models. We are shooting for stop down data on as many models as possible, but it is very time consuming (about half a day per model).


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## ahsanford (Jul 21, 2015)

Bdube said:


> ahsanford said:
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> > AlanF said:
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Wow -- I had no idea the testing was so machine intensive. So much for quick buck for testing people's lenses.

- A


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## lux (Jul 21, 2015)

drat…my plan on bringing a few of my lenses down from St. Louis to Memphis with a keg of beer in hopes of getting my lenses tested looks to be impossible…perhaps someday

But don't think I'm not visiting the next time I'm in Memphis for some kids soccer tournament just to say thank you for all the information. Heck I'll bring beer then too. I really do appreciate all the information he puts out there and I've enjoyed his blog. I know I've never rented a lens but I have made purchases…come to think of it there a couple things I need…


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## bholliman (Jul 21, 2015)

Excellent news! Two of the sites I most respect working together can only be a positive.


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## ahsanford (Jul 22, 2015)

bholliman said:


> Excellent news! Two of the sites I most respect working together can only be a positive.



In other news, two other highly trusted resources -- Ken Rockwell and DXO -- have join forced to become KRoXO, the world leader in all matters of pixel peeping.

- A


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## kaihp (Jul 22, 2015)

Bdube said:


> These are tested on the ImageMaster, but the price would probably be north of that for a lens test, even with the level of automation I have implemented, because it ties up the machine for quite a while.
> 
> We won't be doing variance for lenses as we stop them down for more than 1 or 2 models. We are shooting for stop down data on as many models as possible, but it is very time consuming (about half a day per model).



Brandon,

I noticed that there are only primes in the database so far - and only up to 135mm. Are there any technical or machine/human-time limitations to doing zooms and longer telephoto lenses, or will they come in the (distant?) future?

Big thanks for putting this up together with Bryan.


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## siegsAR (Jul 22, 2015)

@ahsanford
I heard DxO offered to partner w/ Bryan and Roger with this one, but the latter two can't understand their datum rather the computation formulas.  Ken just doesn't care.


On a more _serious_ note, this is a very good collaboration.


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## RGF (Jul 22, 2015)

ahsanford said:


> Bdube said:
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> > ahsanford said:
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Too bad you can not send a lens or two (different copies of the same lens) and have Roger pick the sharpest lens for you. Sounds like this might be an expensive service. Not to mentions, retailers would hate it.


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## RogerCicala (Jul 22, 2015)

kaihp said:


> Bdube said:
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> 
> > These are tested on the ImageMaster, but the price would probably be north of that for a lens test, even with the level of automation I have implemented, because it ties up the machine for quite a while.
> ...



The machine is technically limited to 200mm but we've done some baling-wire-and-duct-tape modifications and have gotten MTF curves for lenses up to 400mm. Stay tuned, we should have a number of longer lens MTF curves out next week.


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## kaihp (Jul 22, 2015)

RogerCicala said:


> kaihp said:
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> > Bdube said:
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Thanks Roger, I'm looking forward to that


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## Mt Spokane Photography (Jul 22, 2015)

I looked at a number of curves this morning. I compared the 17mm TS-E for MTF and Variability with first the 100mmL and then the 135mm L. Both the 100L and the 135mm L had nice looking MTF curves. lower MTF numbers by a tad, but they held up nicely toward the edges.

When mounted to a camera, you don't see this as much.

I was certainly impressed with the curves.


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## Bdube (Jul 23, 2015)

The TS-E 24mm and 17mm are all tilted a little one way or another. It is just the nature of making a lens that is tiltable by its very nature. The "sharp side" of a given 24 or 17 TS-E will be better than a 135L, which are quite consistent. There is also the issue of the coverglass, which the 135L would not be designed for while the 24 and 17 TS-Es would be designed for. It makes a somewhat small difference, but it is there.


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