July 22, 2002



Cognex Corporation
One Vision Drive
Natick, MA 01760


Dear Ladies and Gentlemen:

         We are counsel to Cognex Corporation, a Massachusetts Corporation (the
"Company"), and as such counsel we are familiar with the corporate proceedings
taken in connection with the adoption of the Company's 1998 Stock Incentive Plan
and the amendment thereof adopted in July 2001 (collectively the "Plan"). We are
also familiar with the Registration Statement on Form S-8 to which a copy of
this opinion will be attached as an exhibit.

         As such counsel, we have examined the corporate records of the Company
including its Restated Articles of Organization, as amended, By-laws, Minutes of
Meetings of its Board of Directors and Stockholders and such other documents as
we have deemed necessary as a basis for the opinions herein expressed.

         Based upon the foregoing, and having regarding for such legal
considerations as we deemed relevant, we are of the opinion that:

1. The  Company is  validly  existing  as a  corporation  and in good  corporate
standing under the laws of the Commonwealth of Massachusetts.

     2. The Company has duly reserved  9,743,798  shares of common stock,  $.002
par value per share ("Common Stock") for issuance under the Plan.

     3. The shares of Common Stock issuable  pursuant to the Plan have been duly
authorized,  and when  issued in  accordance  with the  terms of the Plan,  such
shares will be validly issued,  fully paid and  nonassessable  shares of capital
stock of the Company to which no personal liability will attach.

         We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement on Form S-8 and to reference to us under the caption
"Interest of Named Experts and Counsel" in the Registration Statement.


                                        Very truly yours,

                                        /s/Hutchins, Wheeler & Dittmar

                                        Hutchins, Wheeler & Dittmar
                                        A Professional Corporation