Bias

[neuroanatomist]

Not sure who you consider to be "major contributors"

I suspect iND was referring not to forum contributors, but rather site sponsors, e.g. is TDP compensated by Canon, B&H, etc. In that regard, from what I've seen, Bryan et al. are pretty transparent about that - obviously, the site hosts advertisements, and purchasing items using links from the site results in a small percentage returned to TDP. In the reviews, Bryan generally includes statements like 'two copies purchased retail'. I believe he purchases almost all of the gear he reviews through standard retail channels, although I suspect he receives 'consideration' solely in the form of being put near the top of the pre-order queue for new gear - and really, that's in everyone's best interests! When he is sent evaluation copies, he says so, e.g. "At B&H Photo's urging, I accepted an Oben brand ball head with a review promised," or, "I consented to having a CB Gimbal sent to me with my promise to create this review."

[peety3]

... although I suspect he receives 'consideration' solely in the form of being put near the top of the pre-order queue for new gear - and really, that's in everyone's best interests!

Playing devil's advocate for a minute, I have to ask: is it really in everyone's best interests? Why not get Bryan head-of-line privileges with one or more rental shops, so he can test a fresh camera and then return it to the rental pool, alongside ONE purchased camera? Otherwise, those of us who want to buy the product regardless of review don't have to wait for one more camera to be released into the sales pool (or bought by the rental houses to be released into the rental pool). For those who believe in buying new, that second camera might only be in Bryan's hands for a couple weeks, but it's not going back into the new queue when Bryan is done.

I say this after waiting 7 weeks for a 1D Mark III, but also with the hopes of renting the (JUST A RUMOR, FOLKS) new 100-400 for my July cruise instead of the 200-400.

[HDNitehawk]

I suspect iND was referring not to forum contributors, but rather site sponsors, e.g. is TDP compensated by Canon, B&H, etc. In that regard, from what I've seen, Bryan et al. are pretty transparent about that - ...

+1

I have always been suspicious of reviews, what interest do they have in the product. Sometimes you can read in to a review by knowing where they are coming from. When the review uses the same Hype that the manufacture uses it makes me look at the review even closer to see if there is bias.

Of course when I first started this hobby I would read over Bryans reviews and watch for tells of bias. After a few purchases I noticed my comparison to what I had in hand was accurate to Bryan's reviews. One thing that stands out to me is that many of his reviews he tested more than one copy. He found multiple copies with problems (for instance the 24-70 II). In his review he tells you this. IMO the reviews on TDP are not bias, they are provided to sell you a piece a gear of course(click the buy button) but it seems the reviews are geared more toward you buying the right gear and rewarding the site owner for his work in reviewing by buying the gear through the site.

As for the members here I will use myself as an example, I would give you a bias answer if you asked whether Canon is better than Nikon.
If you asked about a certain piece of gear that I own while I would try to answer accurately but pride of ownership may come in to play. For example it is a fact known to me that I own the best 24-70mm f/2.8L II ever made. I would be bias in this way and I am not trying to sell anything.

[Dave Throgmartin]

One lens I've seen that sparks debate on the forums is the TDP ISO crops of the Tamron 70-300. My father in law owns both the Canon 70-300 IS and the Tamron. His A1 goto tele lens is the Tamron. When you compare the IQ results on various review sites these two lenses are basically the same.

The ISO crops for the Tamron 70-300 are abysmal on the long end. It appears something was wrong with Bryan's copy when you compare versus images people capture and some of the other review sites.

Some people cry bias, but I think they don't understand that not all copies are the same. In cases like this where something appears wrong testing a 2nd copy could be worth considering.

Dave

[HDNitehawk]

One lens I've seen that sparks debate on the forums is the TDP ISO crops of the Tamron 70-300. My father in law owns both the Canon 70-300 IS and the Tamron. His A1 goto tele lens is the Tamron. When you compare the IQ results on various review sites these two lenses are basically the same.

The ISO crops for the Tamron 70-300 are abysmal on the long end. It appears something was wrong with Bryan's copy when you compare versus images people capture and some of the other review sites.

Some people cry bias, but I think they don't understand that not all copies are the same. In cases like this where something appears wrong testing a 2nd copy could be worth considering.

Dave

He owns the Canon 70-300mm IS or the 70-300mm IS L??

[Dave Throgmartin]

He owns the Canon 70-300mm IS or the 70-300mm IS L??

He has the Canon 70-300 IS (non-L) and Tamron 70-300 VC. I'm not trying to say the Tamron is an L lens, but most people who've used both or other review sites who've reviewed both typically have them at least as a push when it comes to sharpness.

From what he's told me image quality between the two are similar, but his keeper rate with the Tamron is higher due to faster autofocus and better vibration control than his Canon lens.

Any criticism of TDP bias seems to be tied to 3rd party lenses. I don't think this is true and can point to the Sigma 35 and Tamron 150-600 as evidence that very good 3rd party lenses are shown to be quite good on TDP.

Dave

[HDNitehawk]

Dave if that is the case look at the ISO charts again, it looks to me that the Tamron is arguably a bit better than the Non L IS 70-300mm.

I say arguably because in different parts of the frame one or the other might be a bit ahead.

[Dave Throgmartin]

Dave if that is the case look at the ISO charts again, it looks to me that the Tamron is arguably a bit better than the Non L IS 70-300mm.

I say arguably because in different parts of the frame one or the other might be a bit ahead.

Sorry, I didn't intend to derail iND's thread!

I should have been more clear. I'd agree that the 100, 135, and 200mm shots look like you would expect and are equivalent to 70-300 IS, but the Tamron 300mm shots in the center fall off and, IMHO, are clearly in the poor range. You're right that the 70-300 IS is poor at 300mm in the mid-frame and corners, but looks decent for the price point in the center.

I hesitate to post other people's pictures in forum threads (but it's family right?), but IMHO this is a pretty good result for a $350 lens for a 2298 x 1532 crop at 300mm length likely SOOC without any unsharp mask, etc... applied.

(This is the Tamron 70-300 VC)


IMG_3379 by kmohr60, on Flickr

Dave

[DavidEccleston]

Flickr says it was shot at f/8. The full res pic compared to Bryan's Iso chart at f/8 don't seem that different to me. Both slightly soft, but usable.

[HDNitehawk]

I owned the 70-300mm Non IS, I bought it as part of my first digital kit a 50D. The lens did a good job, no doubt from what we see on the ISO the Tamron would be capable as well.

Rather than real world examples a fair comparison would be setting up a cave man chart and controlled lighting and test the two lenses yourself, if your father in law would loan them to you. A little pixel peeping could tell you if the ISO charts are accurate to what you have in hand.

I am sure IND would mind if we high jack the thread a little. He pointed out the decline in posting, high jacking a thread to get more post occasionally might be a good thing for this site.